URL auslesen und Weiterleiten

[JensP]

Also, nach dem Aktualisiern klick, funktioniert jetzt gar nüscht mehr..und bekomme folgende Meldung (mit der ich gar aber mal sowas von überhaupt nix anfangen kann) :-) :
Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: Exception in JSP: /temp_jp/WebAuftritt/LoginURL.jsp:10

7:   String Weiterleitung3="error.html";
8:   String myvar = request.getParameter("login");
9:
10:   if (myvar.equals("GSS")){
11:    response.sendRedirect(Weiterleitung1);
12:     }
13:   else if (myvar.equals("board")){

Stacktrace:
 org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:504)
 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.temp_005fjp.WebAuftritt.LoginURL_jsp._jspService(LoginURL_jsp.java:51)
 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.

Was is das denn?