Why do I receive a warning about registration status?

To practice in Patent Cases before the USPTO, your status must be considered "Active".  A person in “inactive” status is not authorized to represent others before the Office in patent cases or otherwise engage in the practice before the Office in patent case.  If you receive the warning about "Inactive" practitioner registration status, please contact the Office of Enrollment and Discipline (571-272-4097) to resolve the matter.

USPTO FAQ - Questions and Answers (29AUG2008)