Delete the invisible ICK file ([Job Jacket Name].lck). Then create the new Job Jacket.
The reason for the disabled state of jacket is the presence of an invisible 'jacketname'.lck file at the same location where Job Jacket is stored. When the Job Jackets Manager is opened, the ICK file is created. If you remove the Locked attribute in the Get Info window in the Finder and rename or delete the Job Jacket, the ICK file is not deleted. This ICK file prevents any further job jackets from having the same name and file location.