白酒生产小作坊:各位高手请进关于tomcat服务器的问题？

我已经把Tomcat服务器配置好了，但是浏览其中一个.jsp文件时后会出现错误，具体页面显示如下：
description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

root cause

java.lang.NullPointerException
org.apache.jsp.news.index_jsp._jspService(index_jsp.java:44)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

note The full stack trace of the root cause is available in the Tomcat logs.
各位谁可以帮我解决一下啊？
<form name="login" action="check.jsp" method="post">
<span class="1">用户名：<input type="text" name="admin">
<br>
密码： <input type="password" name="password"></span>
<br>
     <input type="submit" value="登陆">
<br>
</form>
</body>
</html>
<%
String error=request.getParameter("error");
error=new String(error.getBytes("8859_1"),"gb2312");
if(error==null) {}
else{
%>
<%=error%>
<%
}
%>