There's a bug in the UT2004 serverbrowse code which causes the "cannot connect" problem. I found out about this and applied the fix code that was published on the unreal wiki in CarBall Version 1.4. It's quite possible another mod you have installed has not applied any code to fix this issue

I'm currently attempting to add bot support to CarBall. That's going to take a while so no new releases for a bit

I have got a few other cool little enhancements ready to go so you never know when I might get withdrawl symptoms and release another version

Hahah. Your song rocks! The last line didn't make much sense though. Turn that into a wavfile and I'll include it in a map with cheerleaders singing it over and over whilst jiggling their (.)(.)'s