Thanks a bunch for this! I actually have this game on Steam, and I set it up on my Linux machine today using this patch. I wanted to note, in case anyone else ever happens to follow in my footsteps:
Steam's installation of UT2004 names the 'Maps' directory 'maps' instead, which took me a while to figure out. I was getting this error: 'Failed to enter Entry: Can't find file 'Entry''. It couldn't find the map called Entry, which it loads up on game start. I finally realized that half my maps were in 'maps' instead of the correct 'Maps' directory, and moving them fixed everything right up.
Post edited June 30, 2016 by Dark_Oppressor