Seems reasonably self explanatory to me.  Did you lose a volume somewhere
along the line?  Did you relabel a tape with a new barcode label ( I don't
think that could be it as 3590 cartridges require labels and they aren't
easily removed)?  Do you physically have a tape with label 012413 in the
library or on a shelf someplace?

TSM has looked at the internal label on the tape and determined that label
already exists on a tape it knows about.  It won't relabel that tape for
fear that data will be destroyed.  Could these tapes be refurbished perhaps?
3590 tapes can't be degaussed so any labeling from the previous owners would
still be on the tape.  You may have gotten very unlucky in that the new
tapes you have have internal labels that match your already existing tapes.

The only way around this would be to get the volume 012413 and move the data
off of it.  TSM should then let you label volume 012591 correctly.

Kelly J. Lipp
Storage Solutions Specialists, Inc.
PO Box 51313
Colorado Springs, CO 80949
lipp AT storsol DOT com or kelly.lipp AT storserver DOT com
www.storsol.com or www.storserver.com
(719)531-5926
Fax: (240)539-7175