ServletException: bean not found within scope

HI All,

My app running in Jboss, when I try to click on the menu option. I'm getting following error:

javax.servlet.ServletException: bean descriptionVO not found within scope
at org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:825)
at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:758)
at org.apache.jsp.AddRigMapping_jsp._jspService(AddRigMapping_jsp.java:305)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
.................

and my jsp is

<%@ taglib prefix="c" uri="Standard" %>
<%@ taglib prefix="x" uri="Custom" %>

<html>

<head>
<meta http-equiv="Content-Language" content="en-gb">
<meta http-equiv="Content-Type" content="text/html;CHARSET=iso-8859-1">
<title>Add RigMapping</title>
<link rel="stylesheet" type="text/css" href="styles/pageStyle.css">
<%@ page import="zaa.co.rmba.di.util.Constants" %>

<jsp:useBean id="addlistVO" type="zaa.co.rmba.di.beans.AddListVO" scope="session" />

<SCRIPT LANGUAGE="JavaScript" SRC="javascript/util.js"></SCRIPT>
<SCRIPT LANGUAGE="JavaScript" SRC="javascript/date/AnchorPosition.js"></SCRIPT>
<SCRIPT LANGUAGE="JavaScript" SRC="javascript/date/PopupWindow.js"></SCRIPT>
<SCRIPT LANGUAGE="JavaScript" SRC="javascript/date/CalendarPopup.js"></SCRIPT>
<SCRIPT LANGUAGE="JavaScript" SRC="javascript/date/Date.js"></SCRIPT>
<SCRIPT LANGUAGE="JavaScript" SRC="javascript/util.js"></SCRIPT>

<jsp:useBean id="descriptionVO" type="zaa.co.rmba.di.beans.DescriptionVO" scope="session" />

<jsp:useBean id="confirmationVO" type="zaa.co.rmba.di.beans.ConfirmationVO" scope="session" />

<jsp:useBean id="dateVO" type="zaa.co.rmba.di.beans.DateVO" scope="request" />
<%@ include file="menu.html" %>
</head>

<body>
<br>
<br>
<hr>
<br>
<h3>Add RigMapping</h3>

<form name="AddRigMapForm" method="POST" action="FrontController?command=AddRigMapping">
<p> </p>
<div class="tdc">
<center>
<table border="0" width="697">
...................................

and my bean is

package zaa.co.rmba.di.beans;

public class DescriptionVO {

private String reportcodeDescription;
private String majorcodeDescription;
private String subcodeDescription;

........................................

}

Any body know, what causing the problem. Any help will be greatly appreciated.

thanks in advance

I donno the actual cause but import the class file and try if it works ..
<%@ page import="zaa.co.rmba.di.beans.DescriptionVO" %>