QA and Dev enviroments work perfectly.
Handlers all implement the IRequiresSessionState marker.
Config File contains:
<pages enableSessionState="true">
and
<sessionState cookieless="AutoDetect" mode="InProc" timeout="20" />
IIS has session state enabled in application properties and Application is running in its own Application Pool….
So big difference in IIS 6 vs IIS 7.
The Session module need to be stated in the httpModules config section, as VS2008 adds a , and adding it to the web.server section does nothing…