ECLPSE开发的一个BBS　有错误提示。看不懂。。请指教

type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: /web/jsp/article_list.jsp(5,0) The value for the useBean class attribute src.com.computer01.entitysuport.ArticlesAssiImpl is invalid.
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)article_list.jsp
<%@ page contentType="text/html; charset=gb2312" language="java"%>
<%@ page import="java.sql.*"%>
<%@ page import="java.util.*"%>
<jsp:directive.page import="src.com.computer01.entitysuport.UsersAssiImpl"/>
<jsp:useBean scope="page" id="articles" class="src.com.computer01.entitysuport.ArticlesAssiImpl" />
<jsp:useBean scope="page" id="boards" class="src.com.computer01.entitysuport.BoardAssiImpl" /> 
<jsp:useBean scope="page" id="pages" class="src.com.computer01.entitysuport.Splitpage" />
<jsp:useBean scope="page" id="users" class="src.com.computer01.entitysuport.UsersAssiImpl" />
<%
String s_BoardID = request.getParameter("BoardID");
long l_BoardID = 0;
try
{
l_BoardID = Long.parseLong(s_BoardID);
}
catch(NumberFormatException ex)
{
out.println("<p align=center>非法操作</p>");
out.println("<div align=\"center\"><input type=\"button\" name=\"btn1\" value=\"返回\" onClick=\"javascript:window.history.go(-1)\"></div>");
return;
}
boards.setBoardID(l_BoardID);
if(!boards.init())
{
out.println("<p align=center>获取讨论区信息失败</p>");
out.println("<div align=\"center\"><input type=\"button\" name=\"btn2\" value=\"返回\" onClick=\"javascript:window.history.go(-1)\"></div>");
return;
}

articles.setBoardID(l_BoardID);
ResultSet rs = articles.show_board_articles();
pages.initialize(rs,5);

String strPage=null;
int showPage = 1;
//获取跳转到的目的页面
strPage=request.getParameter("showPage");

if (strPage==null)
{
showPage=1;
}
else
{
try
{
showPage=Integer.parseInt(strPage);
}
catch(NumberFormatException e)
{
showPage = 1;
}
if(showPage<1) 
{
showPage=1;
}
if(showPage>pages.getPageCount()) 
{
showPage=pages.getPageCount();
}
}

//获取要显示的数据集合
Vector vData=pages.getPage(showPage);
%><html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>欢迎光临音乐无极限论坛</title>
<link rel=stylesheet type=text/css href="./lib/bbs.css">
</head>
<body bgcolor="#f8f5ff">
<div align="center">
<h2 style="font-family:宋体, sans-serif;"><%=boards.getBoardName()%></h2>
<table width="100%" border="0" cellpadding="0" cellspacing="1">
<tr>
<td width="10%" bgcolor="#3366cc" align="center" height="20"><strong><font color="#FFFFFF">讨论区</font></strong></td>
<td width="10%" align="center" height="20"><a href="good_article_list.jsp?BoardID=<%=l_BoardID%>" target="_self"><font color="#0000FF">精华区</font></a></td>
<td width="35%" height="20">&nbsp;</td>
<td width="15%" align="left" height="20">文章数：<font color="#0000FF"><%=pages.getRowCount()%></font></td>
<td width="30%" align="left" height="20">版主：
<font color="#0000FF">
<%
if(boards.getBoardMaster1() != null || boards.getBoardMaster1() != "")
{
out.print(boards.getBoardMaster1()+"&nbsp;");
}
if(boards.getBoardMaster2() != null && boards.getBoardMaster2() != "")
{
out.print(boards.getBoardMaster2()+"&nbsp;");
}
if(boards.getBoardMaster3() != null && boards.getBoardMaster3() != "")
{
out.print(boards.getBoardMaster3()+"&nbsp;");
}
%></font>
</td>
</tr>
</table>
<table width="100%" border="0" cellpadding="0" cellspacing="1">
<tr bgcolor="#3366cc">
<td width="15%" height="20" align="center"><font color="#FFFFFF">作者</font></td>
<td width="20%" height="20" align="center"><font color="#FFFFFF">发布时间</font></td>
<td width="45%" height="20" align="center"><font color="#FFFFFF">文章标题</font></td>
<td width="10%" height="20" align="center"><font color="#FFFFFF">阅读数</font></td>
<td width="10%" height="20" align="center"><font color="#FFFFFF">回复数</font></td>
</tr>
<%
for(int i=0;i<vData.size();i++)
{ 
//显示数据
String[] sData=(String[])vData.get(i);
long l_UserID = Long.parseLong(sData[2]);
users.setUserID(l_UserID);
if(users.init())
{

%>
<tr  <%if(i%2 ==0) out.print("bgcolor=\"#F7F7F7\""); else  out.print("bgcolor=\"#E6E6E6\"");%>>
<td height="20" align="center"><font color="#0000FF"><%=users.getUserName()%></font></td> 
<td height="20" align="center"><%=sData[5]%></td>
<td height="20" align="left"><a href="article_detail.jsp?ArticleID=<%=sData[0]%>" target="_self"><font color="#0000FF"><%="&nbsp;"+sData[1]%></font></a></td> 
<td height="20" align="center"><%=sData[3]%></td> 
<td height="20" align="center"><%=sData[4]%></td> 
</tr> 
<%
}
}
%>
</table>
<p>
<form action="article_list.jsp" method="post" target="_self">
[<a href="./login/add_article_form.jsp?BoardID=<%=l_BoardID%>&ArticleID=0" target="_self"><font color="#0000FF">发表文章</font></a>]&nbsp;
第<font color="#FF0000"><%=showPage%></font>页/共<font color=red><%=pages.getPageCount()%></font>页&nbsp;
<a href="article_list.jsp?showPage=1&BoardID=<%=l_BoardID%>" target="_self"><font color="#0000FF">[首页]</font></a>&nbsp;
<%
//判断"上一页"链接是否要显示
if(showPage > 1)
{
%>
<a href="article_list.jsp?showPage=<%=showPage-1%>&BoardID=<%=l_BoardID%>" target="_self"><font color="#0000FF">[上一页]</font> </a>&nbsp;
<%
}
else
{
%>
[上一页]&nbsp;
<%
}
//判断"下一页"链接是否要显示
if(showPage < pages.getPageCount())
{
%>
<a href="article_list.jsp?showPage=<%=showPage+1%>&BoardID=<%=l_BoardID%>" target="_self"><font color="#0000FF">[下一页]</font> </a>&nbsp;
<%
}
else
{
%>
[下一页]&nbsp;
<%
}
%> 
<a href="article_list.jsp?showPage=<%=pages.getPageCount()%>&BoardID=<%=l_BoardID%>" target="_self"><font color="#0000FF">[尾页]</font> </a>&nbsp;
转到
<select name="showPage">
<%
for(int x=1;x<=pages.getPageCount();x++)
{
%>
<option value="<%=x%>" <%if(showPage==x) out.println("selected");%> ><%=x%></option>
<%
}
%>
</select>
<input type="hidden" name="BoardID" value="<%=l_BoardID%>">
页&nbsp;
<input type="submit" name="go" value="提交"/>
</form>
</p>
<%rs.close();%>
</div>
</body>
</html> ArticlesAssiImpl.java 
package src.com.computer01.entitysuport;import java.sql.*;
import java.util.List;import src.com.computer01.entity.AllEntity;
import src.com.computer01.entity.TAB_ARTICLES;
PS:因为篇幅过长。第二个文件就给出头文件。。如果有要整个项目的　可以上传。  

小弟是初学者，忘高手详细讲解。。谢谢