500 internal error on requestDispatcher.forward for Experience Manager

Hi

We have a form when submitted calls a webservice and may return error messages as response. We need to redirect to same page posting the error.

trying with this code in POST.jsp of the form, but it returns a 500 server error and couldnt find anything in logs:

SlingHttpServletRequest req =

       new SlingHttpServletRequestWrapper(((SlingHttpServletRequest)slingRequest )) {

           public String getMethod() {

               return "GET";

          }

       };

       // req.setAttribute("PARAMS", paramsMap);

        slingRequest = (SlingHttpServletRequest)req;

        RequestDispatcherOptions requestDispatcherOptions = new RequestDispatcherOptions();       

        RequestDispatcher requestDispatcher = req.getRequestDispatcher(req.getRequestURI(), requestDispatcherOptions);

      if(requestDispatcher != null)

        requestDispatcher.forward(req, response);        

Any pointers on what could be wrong here? Thanks!