Have you got Net Framework 1.1, 2.0 & 3.5 installed.
I can't remember which version it uses off the top of my head. I am currently rebuilding a machine and to be on the safe side installed all the above. I didn't bother with 4 as that seems to want SP3 installing and that will break FFB on my wheels. 1.1 & 2.0 will install with XP SP1, 3.5 needs to have SP2 and Windows Installer 3.1