Office 2003 is not protected, as far as the actual cd goes. It's protection is based upon a unique key, activiation, and updates that also within themsleves sometimes search for invalid or illegal keys.
Aside that, sounds like you have a software problem, not a problem with respect to copy protection.
Thread will be moved to General Software Forum.
Also, please provide moreinformation for help in this matter, what you have provided so far is very vague.