Hi,
I'm pretty sure the problem is that, in order to run on a 64-bits platform, you need:
- the correct version of the program (warning: it's ANOTHER executable, it's compiled expressely for Win-64)
- the correct license for it; it's not the same "Feature" nor the same ID, etc...
From the O.P. I understood that you were trying to install on a "regular" version of XP, not XP64...
Most probably you do have to contact your reseller, explain the problem to him and have the license converted (and, if you don't already have it, get the corerct installation CD).
Regards