Alway check to see what type or types of licenses they using. i.e. Stand alone or License Manager.
For issues that only apply to License Manager you will see (LM) in the title of the article in the Related resources below. The other links apply to a Stand alone set up or both Licesne Manager and Stand alone licenses.
Please see links below for possible solutions to this problem. The list below in Related Resources might be able to help determine the issue.