I had this same issue about a year ago. The problem was attached to a user on our domain. The domain user could go to any machine and get the same error, while no one else had any problems. I looked through my email to see how we resolved it, but it must have been resolved over the phone. I think we had to delete some files(or registry entries) for them to repopulate, or maybe we just reinstalled rhinoCam for that user. Sorry I can't remember exactly what we did, but it was definitely tied to the user account. Have you tried another user account?