except ULX installed.
SVN ULX requires SVN of ULib.
XGUI requires SVN of both.
Does ULX work for you, without XGUI?
"ulx help" should show you many commands if you've added yourself as superadmin using the typical Gmod users file referenced on this forum, the Gmod Wiki, our text file, and several hundred other Gmod help sites. "ulx who" will show you as superadmin (again, if you added yourself correctly)
If it's not loading and you have it installed properly, an error will be occuring on the server somewhere (at startup, player join, or attempted command run)