Session problem

[Kishore Shewani]

Dear friends,
I have a Jsp (rendered on Tomcat 4.1) from which i am opening a pop-up window to display a report on Segate page server.
The call is made somewhat like this
Window.open("http://server:8080/reports/name.rpt?query string" ,param list ......);
The IIS server (listening at 8080) redirects the request to Crystal report server ( Segate page server ).
The problem am facing is that the session on Tomcat server is lost as soon as i view a report. Surprisingly this doesn't happen for some reports.
The only difference between reports is the number of parameters in query string. I could not figure out the reason.
Can anybody help me out with possible reasons.
(I have already tried out with length of query string any the number of parameters )
Thanx

[Nathan Pruett]

Are you using cookies or URL rewriting to track sessions?

Be sure to use HttpServletResponse.encodeURL() on the URL you are using to open the window to support URL rewriting, and change your browser settings to 'ask before accepting cookies' (or however they word it) so you can see if the session id cookie is being overwritten.