I have the same problem as I did with the demo from PC Format, although that had a 45 day trial!
Anyway, I've fixed it by uninstalling the program, searching for 'fps' in the registry and deleting any entries that came up that were related to FPS creator. (use regedit from the run command).
Now be careful in regedit, if you make any changes that don't relate to FPS creator you could damge windows beyond repair. Just use a bit of common sense, I only deleted entries that I was sure were related to FPS creator and nothing more, plus ignore any that are just about recently used programs or folder structures, that's what I did anyway!
Hope that works for you too.....