这是不是没连上数据库问题

错误：
HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
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)
root cause java.lang.NullPointerException
org.apache.jsp.add_005ffriend_005fsave_jsp._jspService(add_005ffriend_005fsave_jsp.java:90)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
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)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.17 logs.
--------------------------------------------------------------------------------Apache Tomcat/5.5.17
源代码：
<%@ page contentType="text/html;charset=gb2312" language="java"%>
<%@ page import="java.sql.*" %>
<! DOCTYPE HTML  PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
    <meta http-equiv="Content-Type" content="text/html;charset=gb2312">
    <title>欢迎光临网上通讯录</title>
    <link rel=stylesheet type=text/css href="./lib/bbs.css">
    <jsp:useBean scope="page" id="Friend" class="com.zk.Friend"/>
<jsp:useBean scope="page" id="Pal" class="com.zk.Pal"/>
<jsp:useBean scope="page" id="ExecuteDB" class="com.zk.ExecuteDB"/>
 </head>
 <body bgcolor="#F5F5F5">
 <div align="center">
 <form name="add_friend_save" method="post" action="add_friend_form.jsp" target="_self">
 <% request.setCharacterEncoding("gb2312");
    long lUserID=(Long)session.getAttribute("UserID");
    String sFriendID=request.getParameter("FriendID");
    long lFriendID=Long.parseLong(sFriendID);
    Pal.setUserID(lUserID);
    Pal.setFriendID(lFriendID);
    if(Pal.add())
      {out.println("<p align=center><font color=blue>恭喜你添加成功！</font></p>");
       out.println("<p><input  type=\"button\" name=\"btn\" value=\"&nbsp;确定&nbsp;\"onClick=\"javascript:window.location='add_friend_form.jsp'\"></p>");
      }
    else
      {out.println("<p align=center><font color=blue>你的操作失败！</font></p>");
       out.println("<p><font color=red>"+ExecuteDB.getErrMes()+"</font></p>");
       out.println("<p><input type=\"button\" name=\"btn\" value=\"&nbsp;返回&nbsp;\"onClick=\"javascript:window.history.go(-1)\"></p>");
      }
 %>
 </div>
 </body>
 </html>