I was about to suggest this. A few years back on the Lix instagib server I had the same problem I think. It has something to do with the s3tc textures being incorrectly installed on the client or the server. What happens is that you can enter the server but you can't move and your say messages appear in white like an event message.
How to feck up a perfectly good game:
UT (1999) = UnbelievableGameSoCoolIMustHelpBringNewPlayers Tournament
UT (2008) = Unreal ThrustMyPrivatePartsInYourFaceBish
And that's probably why UTIII was a relative flop. New game, same sh*thead players ^^.