I have a similar problem except that i cant find my UI folder anymore, meaning i cant install HUDS maps etc... I'll explain how it came to be, as soon as I installed OSX 10.5 and opened tremulous (it having been preserved from the OS change) i went into a server and noticed i didnt have that map and it was a fairly large one (hamu), so i went online, got the map file and looked for the UI folder but couldn't find it all that was contained within the base folder was the default maps, a file titled data-1.1.0.pk3, maprotation.cfg, server.cfg, and vms-1.1.0.pk3, so i figured i'd right click on the tremulous application icon and click "show package contents". once i entered the folder and opened the contents i found another folder entitled 'base' but the only things in there were a bunch of files with the suffix .dylib so to my dismay i waited 2 hours for all of hamunaptra to download, which was quite annoying, so i was wondering if anyone could help me fix my problem, I think I have provided enough details =D