It sounds like any one of several issues can be going on. The ones that immediately come to mind relate to cookies, javascript, session state, etc.
I got around a similar issue by using an HttpWebRequest to the first (Main) page to obtain a state variable which was stored in the URL used to go to the next (Details) page. However, that is not the only way to store session, so more information about your specific issue is needed. Are you familiar with HttpWebRequest and HttpWebResponse?
Sanford ("Sandy") J. Asman
Attorney at Law
570 Vinington Court
Atlanta, GA 30350
Phone: (770) 391-0215
Fax: (770) 668-9144
Email: sandy@asman.com