I just cannot get this game (Clive Barkers Undying) to install on the system i just built my GF

as stated in the title, its a P4 HT (not dual core), an Abit board, 1gig OCZ DDR2, X800GTo, XP pro SP2. it gets to 60% then gives an 'install error, please try again'.
I tried compatibility, turning off advanced txt etc, switched HT support off, same result.
It installs and plays flawlessly on my opty machine (specs as shown), but I haven't been able to get it to work with either of the machines I've built around that P4 cpu , which is why i think that it's the culprit.
Ideas anyone?? she really badly wants to play it
(oh, and no crazy talk along the lines of "why not let her use your comp niceguyrichy?"
)
thanks in advance