Exception:500 org.apache.jasper.JasperException: java.lang.NullPointerException

I am using netbeans 6.8,struts 1.3 & glassfish v3 server.I am getting this exception .please help.

index.jsp

struts-config.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts-config PUBLIC
          "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
          "http://jakarta.apache.org/struts/dtds/struts-config_1_3.dtd">

<struts-config>
    <form-beans>
     <form-bean  name="pointForm"
    type="org.apache.struts.validator.DynaValidatorForm">
    <form-property  type="int"
    name="id"  initial="-1"/>
    <form-property  type="double"
    name="x"  initial="0"/>
    <form-property  type="double"
    name="y"  initial="0"/>
    <form-property  type="java.lang.String"
    name="color"  />
    </form-bean>
    </form-beans>
    
    <global-exceptions>
    
    </global-exceptions>

<global-forwards >
        <forward
            name="add"
            path="/Add.do" />
    </global-forwards>

<action-mappings>
       <action path="Add" forward="add.jspx"/>
    </action-mappings>
    
    <controller processorClass="org.apache.struts.tiles.TilesRequestProcessor"/>

<message-resources parameter="com/myapp/struts/ApplicationResource"/>
    
    
    <!--
    This plugin initialize Tiles definition factory. This later can takes some
    parameters explained here after. The plugin first read parameters from
    web.xml, thenoverload them with parameters defined here. All parameters
    are optional.
    The plugin should be declared in each struts-config file.
    - definitions-config: (optional)
    Specify configuration file names. There can be several comma
    separated file names (default: ?? )
    - moduleAware: (optional - struts1.1)
    Specify if the Tiles definition factory is module aware. If true
    (default), there will be one factory for each Struts module.
    If false, there will be one common factory for all module. In this
    later case, it is still needed to declare one plugin per module.
    The factory will be initialized with parameters found in the first
    initialized plugin (generally the one associated with the default
    module).
    true : One factory per module. (default)
    false : one single shared factory for all modules
    - definitions-parser-validate: (optional)
    Specify if xml parser should validate the Tiles configuration file.
    true : validate. DTD should be specified in file header (default)
    false : no validation

Paths found in Tiles definitions are relative to the main context.
    -->
    <plug-in className="org.apache.struts.tiles.TilesPlugin" >
        <set-property property="definitions-config" value="/WEB-INF/tiles-defs.xml" />      
        <set-property property="moduleAware" value="true" />
    </plug-in>
    
    
    <plug-in className="org.apache.struts.validator.ValidatorPlugIn">
        <set-property
            property="pathnames"
            value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml"/>
    </plug-in>
  
</struts-config>

add.jspx

<?xml version="1.0" encoding="UTF-8"?>

<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page"
          xmlns:fmt="http://java.sun.com/jsp/jstl/fmt"
          xmlns:c="http://java.sun.com/jsp/jstl/core"
          xmlns:html="http://struts.apache.org/tags-html"
          xmlns:fn="http://java.sun.com/jsp/jstl/functions"
          xmlns:bean="http://struts.apache.org/tags-bean" version="2.0">
    <jsp:directive.page  contentType="text/html" pageEncoding="UTF-8"/>
    <html:xhtml/>
    <html:html >
        <head>
            <title>
               <bean:message key="add.title"/>
             </title>
         </head>
        <body>
            <h1>  
                <bean:message key="global.heading"/>
                <jsp:text></jsp:text>
             <bean:message key="add.heading"/>
             </h1>
             <html:errors/>
             <html:form  action="/add">
                 <table class="addedit" >
                     <tr>
                         <td>
                             <fmt:message key="pointForm.prompt.x"/>
                          </td>
                          <td><html:text name="pointForm" property="x"/></td>
                      </tr>
                      <tr>
                          <td>
                             <fmt:message key="pointForm.prompt.y"/>
                          </td>
                          <td><html:text name="pointForm" property="y"/></td>
                      </tr>
                      <tr>
                          <td>
                              <fmt:message key="pointForm.prompt.color"/>
                           </td>

</tr>
                         <tr>
                           <td>
                               <html:submit>
                                   <fmt:message  key="pointForm.add.submit"/>
                               </html:submit>
                           </td>
                         </tr>

</table>
            </html:form>

</body>
    </html:html>
</jsp:root>