Yep the guys have epic have spotted a few serious bugs and have so relased an udpate which fixes:
Fixed support for Voodoo3 / Matrox G400.
- Fixed initial framerate hitches in network play.
- Fixed the jittery screen updates in the server browser when sorting by ping.
- Fixed a possible DoS attack in the server code.
- Fixed a few other minor potential crashes.
You can find a host of mirrors here
http://www.unrealtournament2003.com/?downloads