My best guess is maybe the registry entries that point to the UO installation folder could be wrong. Since 64bit XP likes to install things into "C:\Program Files x86" (something like that) versus plain "C:\Program Files", something funny can be going on with the pathnames. You can try choosing a custom installation folder something like "C:\Games\UO"
that was the problem earlier... the patch wouldnt install in the regular program files so i changed it, installed and patched fine
then i had this map0 problem....
so i just reinstalled everything.. now im getting a error when the UO login screen comes up.. its in full screen doesnt show anything.. and becomes not responding after a few secs...
anyway to make it windowd mode without entering the game>?