There has been a patch released to address some issues that had slipped through testing. The main issues being addressed are missing Esc menus while running KOTH w/o the Chaos mutator, and the lockups experienced by some when using the crossbow. Both have been fixed. The patch is available here:

Chaos HotFix -FineWolf's HQ

Chaos HotFix -FurrySound.net

Simply extract all 4 files to your UT2003/Sytstem folder.

This patch has been installed on the Chaos public server.

Also - please be sure you are running v2225 patch and the bonus packs from Epic and Digital Extremes. Get them from PlanetUnreal These are required for Chaos to work!