fbackup errors

[Ian Lochray]

About a week ago, my backups started to fail every night with the errors below. It's a QUANTUM DLT8000. The strange thing is that fbackup fails but tar seems OK. Any ideas?
fbackup(1004): session begins on Thu Jan 13 03:15:00 2011
fbackup(3205): WARNING: unable to read a volume header
fbackup(3024): writing volume 1 to the output file /dev/rmt/1m
fbackup(3012): WRITE ERROR while writing checkpoint record, at media record 0
fbackup(3102): attempting to make this volume salvagable
fbackup(3123): could not read the previous checkpoint record
fbackup(3105): writing 2 EOFs and rewinding the tape
fbackup(3106): please mount a good tape
fbackup(3310): enter '^[yY]' when volume 1 is ready on /dev/rmt/1m,
or '^[nN]' to discontinue:
fbackup(3004): writer aborting
fbackup(1002): Backup did not complete : Reader or Writer process exit

[Dennis Handly]

I assume you tried a new tape?

[Ian Lochray]

Yes I did.
Yesterday I did a big tar which worked fine. I then powered the drive off and on and, for the first time in a week, the fbackup subsequently worked.
I'll keep watching.