Stuck in URL parameter to JSF problem

I'm stuck on this problem. I've googled a lot and I cant find why this is not working. could anyone help me? Any help would be apreciated.

The consulta.jsp is invoked this way: http://localhost:8080/admsite/consulta.jsp?sigla=ECE

my faces-config.xml:

<?xml version='1.0' encoding='UTF-8'?>
<faces-config version="1.2" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_1_2.xsd">
<managed-bean>
    <managed-bean-name>Usuario</managed-bean-name>
    <managed-bean-class>com.itautec.mdi.facades.Usuario</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
</managed-bean>
<managed-bean>
    <managed-bean-name>Servicos</managed-bean-name>
    <managed-bean-class>com.itautec.mdi.facades.Servicos</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
</managed-bean>
<managed-bean>
    <managed-bean-name>StatusDocumentos</managed-bean-name>
    <managed-bean-class>com.itautec.mdi.facades.StatusDocumentos</managed-bean-class>
   <managed-bean-scope>request</managed-bean-scope>
</managed-bean>

<managed-bean>
    <managed-bean-name>Lotes</managed-bean-name>
    <managed-bean-class>com.itautec.mdi.facades.Lotes</managed-bean-class>
   <managed-bean-scope>request</managed-bean-scope>
    <managed-property>
        <property-name>tpSvc</property-name>
        <property-class>java.lang.String</property-class>
        <value>#{param.sigla}</value>
    </managed-property>
</managed-bean>

<navigation-rule>
    <from-view-id>/login.jsp</from-view-id>
    <navigation-case>
	<from-outcome>sucesso</from-outcome>
	<to-view-id>/principal.jsp</to-view-id>
    </navigation-case>
    <navigation-case>
	<from-outcome>falha</from-outcome>
	<to-view-id>/login.jsp</to-view-id>
    </navigation-case>
</navigation-rule>
</faces-config>

my bean code:
[code]package mybeans;

import java.util.Arrays;
import java.util.List;

public class Lotes {

private String tpSvc = "";
   //some other vars

public void setTpSvc(String tpSvc) {
        System.out.println("tpSvc = " + tpSvc);
        this.tpSvc = tpSvc;
    }
    // some other getter/setters

My jsp page:

<%@page language="java" contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="h" uri="http://java.sun.com/jsf/html"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@taglib prefix="f" uri="http://java.sun.com/jsf/core"%>
<%@taglib prefix="a4j" uri="http://richfaces.org/a4j"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"   "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
	<title>MDI - Processamento de Depósitos por Imagem</title>
	<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
        <script type="text/javascript" language="javascript" src="../scripts/menu.js"></script>
	<link href="../css/mdi.css" rel="stylesheet" type="text/css">
    </head>

<body bgcolor="#B7CCE0" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
    <f:view>
[color=red]    <h:outputText value="#{Lotes.tpSvc}"/>
[/color]    <a4j:outputPanel ajaxRendered="true" id="saida">
        <h:form id="lotes">
            <br/>
            <table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
                <tr>
                    <td width="95%">
                        <span class="caminhoSelecionado">Gestão >></span>
                        <span class="caminhoSelecionado">Consulta</span>
                    </td>
                    <td width="5%" valign="bottom">
                        <div align="right">
                        </div>
                    </td>
                </tr>
                <tr>
                    <td colspan="2">
                        <img src="../images/linha.gif" width="100%" height="1">
                    </td>
                </tr>
            </table>
            <table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
                <tr>
                    <td height="20" valign="bottom"> </td>
                </tr>
            </table>
            <table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
                <tr>
                    <td width="65%" valign="bottom">
                        <table border="0" cellspacing="0" cellpadding="0">
                            <tr>
                                <c:forEach var="svc" items="#{Servicos.lista}">
                                    <c:choose>
                                        <c:when test="${empty param.sigla}">
                                            <c:set var="img" value="../images/aba-cinza.gif"/>
                                            <c:set var="url" value="consulta.jsp?sigla=${svc.sigla}"/>
                                        </c:when>
                                        <c:when test="${param.sigla == svc.sigla}">
                                            <c:set var="img" value="../images/aba-azul.gif"/>
                                            <c:set var="url" value="consulta.jsp?sigla=${svc.sigla}"/>
                                        </c:when>
                                        <c:otherwise>
                                            <c:set var="img" value="../images/aba-cinza.gif"/>
                                            <c:set var="url" value="consulta.jsp?sigla=${svc.sigla}"/>
                                        </c:otherwise>
                                    </c:choose>
                                    <td width="150" valign="middle" background="<c:out value="${img}"/>" class="corMoldura">
                                        <div align="center" class="textoAzul">
                                            <a href="<c:out value="${url}"/>" class="linkAba">
                                                <c:out value="${svc.descricao}"/>
                                            </a>
                                        </div>
                                    </td>
                                    <td width="1" valign="bottom">
                                        <img src="../images/spacer.gif" width="1" height="1">
                                    </td>
                                </c:forEach>
                            </tr>
                        </table>
                    </td>
                    <td width="35%" valign="bottom"> </td>
                </tr>
            </table>

<table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
                <tr>
                    <td width="9" height="20" valign="top" class="corMoldura"> </td>
                    <td class="corMoldura"> </td>
                    <td width="9" height="20" valign="top" class="imagemMolduraDir">
                        <div align="right"></div>
                    </td>
                </tr>
                <tr class="corMoldura">
                    <td> </td>
                    <td valign="top">
                        <table width="100%" border="0" cellspacing="2" cellpadding="2">
                            <tr>
                                <td width="4%" class="textoAzul">Filtros:</td>
                                <td width="96%">
                                    <h:selectOneMenu id="lstStatus" value="#{Lotes.stDoc.sigla}">
                                        <f:selectItems value="#{Lotes.stDoc.lista}"/>
                                        <a4j:support event="onchange"
                                                     action="#{Lotes.selectChanged}"
                                                     reRender="saida, msg">
                                        </a4j:support>
                                    </h:selectOneMenu>
                                </td>
                            </tr>
                        </table>
                        <br>

<table width="95%" border="0" align="center" cellpadding="0" cellspacing="0" class="bordaTabela">
                            <tr>
                                <td width="0" class="menuTabela"><div align="center">Agência</div></td>
                                <td width="1" class="fundoTabela"><img alt="" src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabela"> <div align="center">Terminal</div></td>
                                <td width="1" class="fundoTabela"><img alt="" src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabela"><div align="center">Lote</div></td>
                                <td width="1" class="fundoTabela"><img alt="" src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabela"><div align="center">Qtde.</div></td>
                                <td width="1" class="fundoTabela"><img alt="" src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabela"> <div align="center">Valor Inf.</div></td>
                                <td width="1" class="fundoTabela"><img alt="" src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabela"> <div align="center">Valor Final</div></td>
                                <td width="1" class="fundoTabela"><img alt="" src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabela"><div align="center">Status</div></td>
                            </tr>
                            <c:forEach var="lote" items="${Lotes.lista}">
                            <tr>
                                <td width="0" class="menuTabelaTotal"><div align="center"><c:out value="${lote.agenciaId}"/></div></td>
                                <td width="1" class="fundoTabela"><img src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabelaTotal"><div align="center"><c:out value="${lote.terminal.codigoTerminal}"/></div></td>
                                <td width="1" class="fundoTabela"><img src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabelaTotal"><div align="center"><c:out value="${lote.loteID}"/></div></td>
                                <td width="1" class="fundoTabela"><img src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabelaTotal"><div align="center"><c:out value="${lote.qtdeDocumentos}"/></div></td>
                                <td width="1" class="fundoTabela"><img src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabelaTotal"><div align="center"><c:out value="${lote.valorInformado}"/></div></td>
                                <td width="1" class="fundoTabela"><img src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabelaTotal"><div align="center"><c:out value="${lote.valorLote}"/></div></td>
                                <td width="1" class="fundoTabela"><img src="../images/spacer.gif" width="1" height="1"></td>
                                <td width="0" class="menuTabelaTotal"><div align="center"><c:out value="${lote.statusLote.descricao}"/></div></td>
                            </tr>
                            </c:forEach>
                        </table>
                    </td>
                    <td> </td>
                </tr>
                <tr >
                    <td width="9" height="20" valign="bottom" class="imagemMolduraEsqBott"> </td>
                    <td class="corMoldura"> </td>
                    <td valign="bottom" class="imagemMolduraDirBott"><div align="right"></div></td>
                </tr>
            </table>
            <h:messages id="msg"/>
        </h:form>
    </a4j:outputPanel>
    </f:view>
</body>
</html>

And I'm getting this error:

org.apache.jasper.JasperException: javax.faces.FacesException: javax.faces.FacesException: The scope of the referenced object: #{param.sigla} is shorter than the referring object
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:521)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:415)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:336)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.sun.faces.context.ExternalContextImpl.dispatch(ExternalContextImpl.java:408)
com.sun.faces.application.ViewHandlerImpl.executePageToBuildView(ViewHandlerImpl.java:442)
com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:115)
org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:106)
com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:144)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:245)
org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:530)
org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)
org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

root cause

javax.faces.FacesException: javax.faces.FacesException: The scope of the referenced object: #{param.sigla} is shorter than the referring object
com.sun.faces.application.ApplicationAssociate.createAndMaybeStoreManagedBeans(ApplicationAssociate.java:537)
com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:82)
javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:64)
javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:45)
org.apache.el.parser.AstValue.getValue(AstValue.java:86)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:101)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_c_005fforEach_005f1(consulta_jsp.java:925)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_h_005fform_005f0(consulta_jsp.java:357)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_a4j_005foutputPanel_005f0(consulta_jsp.java:224)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_f_005fview_005f0(consulta_jsp.java:156)
org.apache.jsp.gestao.consulta_jsp._jspService(consulta_jsp.java:114)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:336)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.sun.faces.context.ExternalContextImpl.dispatch(ExternalContextImpl.java:408)
com.sun.faces.application.ViewHandlerImpl.executePageToBuildView(ViewHandlerImpl.java:442)
com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:115)
org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:106)
com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:144)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:245)
org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:530)
org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)
org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

root cause

javax.faces.FacesException: The scope of the referenced object: #{param.sigla} is shorter than the referring object
com.sun.faces.config.ManagedBeanFactoryImpl.evaluateValueExpressionGet(ManagedBeanFactoryImpl.java:995)
com.sun.faces.config.ManagedBeanFactoryImpl.setPropertiesIntoBean(ManagedBeanFactoryImpl.java:636)
com.sun.faces.config.ManagedBeanFactoryImpl.newInstance(ManagedBeanFactoryImpl.java:317)
com.sun.faces.application.ApplicationAssociate.createAndMaybeStoreManagedBeans(ApplicationAssociate.java:527)
com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:82)
javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:64)
javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:45)
org.apache.el.parser.AstValue.getValue(AstValue.java:86)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:101)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_c_005fforEach_005f1(consulta_jsp.java:925)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_h_005fform_005f0(consulta_jsp.java:357)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_a4j_005foutputPanel_005f0(consulta_jsp.java:224)
org.apache.jsp.gestao.consulta_jsp._jspx_meth_f_005fview_005f0(consulta_jsp.java:156)
org.apache.jsp.gestao.consulta_jsp._jspService(consulta_jsp.java:114)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:336)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.sun.faces.context.ExternalContextImpl.dispatch(ExternalContextImpl.java:408)
com.sun.faces.application.ViewHandlerImpl.executePageToBuildView(ViewHandlerImpl.java:442)
com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:115)
org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:106)
com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:144)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:245)
org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:530)
org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)
org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)