An error may occasionally occur in the tape library. If this happens during the backup, then you probably have to create tape duplicate without last saved (damaged/incomplete) squence.
But this hapens while reading the tape, there is opportunity that you can only change *ERR status on BRMS with this SQL command
UPDATE QUSRBRM/QA1AMM SET tmcsmc = 'â'
WHERE TMCVSR = 'tape_name' Then, of course, you should solve the problem with the drive in the library.