Tape positioning error on name.
Backup is experiencing difficulty positioning correctly in the current tape.
If doing a restore operation, attempting to restore an entire set may remedy this situation. If this does not solve the problem, as a last resort, modify the Registry so that backup will not do positioning. Use REGEDT32 to change the \\USR\\SOFTWARE\\MICROSOFT\\NTBACKUP\\BACKUP ENGINE\\USE FAST FILE RESTORE key to 0.