System: XP Pro sp3, TP9 build 3928 w/ 5-user home network license
When I use TP9 and launch a second copy, then exit that 2nd instance a bit later, the original instance will pop up an error <8041> saying that my session is not active in the database for multiuser license validation, and the program exits.
This doesn't happen until I have exited the 2nd instance of TP, so, what I think happens is that TP terminates all sessions of the current user instead of just the one that he's closing, and as a result, any other running instances are logged out too.
This is not specific to build 3928, I've seen it in prior TP9 releases too.
I often run multiple instances so I can work on multiple folders at the same time.