Java EE (Java Enterprise Edition) General Discussion

hi experts!!!
I have this problem, you'll see:

this is my jsp that is calling a servlet:

<jsp:forward page="../servlet/URLControlServlet" /></jsp:forward>

ok, then the servlet do some stuff to validate the call:

	xVal = "S";
        String url = "/main/submain/wrkadmin.jsp?test=1&par1=" + xVal;
	//response.sendRedirect(url);
	request.getRequestDispatcher(url).forward(request, response);

and have to go to an other jsp....
but I've got this error:

Error : null 
StackTrace         :
java.lang.NullPointerException at main.submain.wrkadmin_jsp_63._jspService(wrkadmin_jsp_63.java:121) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java(Compiled Code)) at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled Code)) at org.apache.jasper.runtime.JspServlet$JspServletWrapper.service(JspServlet.java(Compiled Code)) at  .......

what can be the problem???

any suggestion would be appreciated!!!

many thanks

LBAEZ