Something smells fishy, never heard of a corporate version of XP wanting to validate.
Actually, I don't think you have to validate corp XP at all...
--BUT--
With each service pack, they also installed a list of keys that they knew were being abused... and if your key was on that list it made it fail validation.
It's real simple... CORP EDITION + GOT IT FROM A FRIEND = PIRATED
LOL