Problem while Backing up drive!

I am backing up my Mac Pro to a backup server (a Power PC G4). Both are running OS X 10.5.4. The version of Retrospect is 6.1.23 and the client is 6.2.222. The backup server says that the client is "responding,", but I continue to get the "Waiting for backup media" message over the past 24 hours. There is a lock icon on the drive that I want to back up.
- Under "Devices," all four of my fire wire external hard drives show up with the note "Content unrecognized."
- If I click "Device Status," the only "Currently visible devices" seems to be the CD drive.
