I didn't have Pyro Audio Creator on my office computer so decided to give it a go (latest Windows 10). I went into my Cakewalk account, downloaded the program (from Nov 30, 2007) and ran it without problem - it accepted my serial and registration numbers when prompted.
Sorry you're having problems. Did you run the initial "installation" as Administrator? i.e. right-clicking on AudioCreator15Setup.exe and selecting "Run as administrator"
Other than that I have no answers/suggestions.