Sorry, I'll try to be more detailed.
OS: Windows XP SP2
I've tried swapping / and \'s around, but...to no avail. Do I perhaps simply need to edit the preference paths, but which one: Prefab Path, or User INI path. And to what do I need to tell it to go to?
I also noticed that other Quake3 games that use GTK, have user0.proj files, because I didn't get one of those...
Note: GTK Radiant works just fine with the standard games...so no problems with GTK itself...just the config files & stuff that point Tremulous out to it.