Petra,
There is apparently a problem with running UOAM on a 64-bit OS. Other people have reported problems with UOAM on XP, Vista, and Windows 7 64-bit systems, but UOAM works on all 3 operating systems in their 32-bit version.
I haven't seen any solution to the problem. 32-bit programs that are driver dependent simply will not run on 64-bit systems without a code overhaul. I don't know if that is specifically what brings UOAM to a halt, but it is likely.
-Skylark