Just for the heck of it, I just installed GnuCash 2.2.0 on Windows XP inside of Parallels (I know GnuCash can run in Mac OS X). It worked out OK:

I did run into an error where the new account druid ended up behind an blank window. I had to force quit, but I think it would have worked out fine. Might have been my low (800x600?) screen resolution.

FYI: GnuCash 2.2.0 was just released over this past weekend (July 15, 2007). More information about it here.