I have read in a german forum that a guy had luck with getting it running when he decided to install it into the default paths, including data paths, instead of his own preferred paths he tried before several times.
Sounds a bit strange to me though, but who knows?
If this does not work as well, what about running it in a virtual XP machine?
The latest released VMWare player (version 3.01?) is able to create/install such a platform - so there should be no need for the full workstation version.
Oh... while writing, I forgot... your XP version has been eaten... oh dang.