how to handle redirets for PPR requests on session time out

[Samba]

Hi,

   We are facing trouble in redirecting the users to login page for PPR
requests after session time out.
   We are having a filter that redirects the users login ( jsp ) page if the
user is not autheticated or the authentication timed out. But after
redirecting,
   I'm seeing the following error in firebug console:

 *["Invalid PPR response. The response-headers were:\nDate: Wed, 22 Jul 2009
09:52:49 GMT\nServer: Apache\n..."]Common1_2_7.js (line 10649)*
*["Error ", TypeError: a5 has no properties message=a5 has no properties, "
delivering XML request status changed to ", function()]*


       1.  I read on the internet that redirects on AJAX requests cannot be
made server side and  can only be made via javascript, is that true?
       2.  I tried adding a PPR hook to identify if the response is
regarding related to session timeout and if yes, then would change the
document location to login page
              however, this is not working as expected; perhaps I'm doing
something wrong.

              Here is what I'm doing:

                  function register(){

TrPage.getInstance().getRequestQueue().addStateChangeListener(callbackMethod);
                   }


                   function callbackMethod(requestEvent)
                   {


if(requestEvent.getStatus()=TrXMLRequestEvent.STATUS_COMPLETE)
                       {

                                      var
response=+requestEvent.getResponseXML());
                                      if(has info about session timeout)
                                             documnet.location="/login.jsp";
                       }
                  }

                  register();

                 But I'm getting error saying requestEvent.getStatus() is
not defined.


              Can some one help me how to redirect users to login page on
PPR requestts?

Thanks and Regards,
Samba