[Bearkiller72]

AAA 1.1 have the mouse version mod??? Where???

It hasn't. That's why I asked you, what you did:

Say, that "6DOF mouse version" you are using, wasn't included in the original UI 1.1 package, right? You installed it afterwards, or not?

I wanted to be sure of what you did, to give you some help that works. :wink:
So, if it is not included (and I think it isn't), there you have your answer:

that would explain, why you can't join: you fail the checksum test, because you are having a modified MODS folder.
My guess is, if you restore your original MODS folder (take the 6DOF mouse version out again), you'll be able to join.

Just test that. I think, this is the problem. Worst case for you is: you can join, but can't use "Mouse 6DOF".