User id not set all the time
Because the users see one menu before they login and one menu afterwards they cannot add/update a main listing before they login because they don't know the insert or update link unless they copy it after they login of course.
I think the session variable is not being set due to cookies being blocked on some machines? Do you agree?
If so we are back to your server variable suggestion which I don't know how to implement and change all my pages?