Welcome to the TH Community, @rja666!
I'm afraid that this error could have occurred due to data or physical/logical corruption on the camcorder's HDD. If you have important data on it, you should definitely contact a professional data recovery company for assistance. Another way for you to troubleshoot the issue would be to use a third-party recovery tool at your own risk to retrieve any important files.
Otherwise, you could try resolving the issue by resetting the camera to factory defaults and formatting the HDD itself. If that doesn't work, I'd definitely consider replacing the HDD. However, you should also check your camcorder's warranty status. If it's still covered, you could possibly be able to RMA the product and get the faulty hardware replaced by the manufacturer's customer support.
Contact them for further assistance.
Hope this helps you. Good luck!