whenever i join a server this error comes up:
(its in the attachments)
can anyone help me?

I have the same problem
The game runs smoothly but impossible to play online

I don't even own the game for PC, so I don't know the solution. But if you're still having problems with the game, then you should repost this in the 'Questions/Problems' instead of in 'Discussion' like it is now.
And I hope someone figures out what your problem is/was, because I really want to buy UT. And no way am I buying it if online play doesn't work! lol.