TL891DLX Tape Drive / Firmware upgrade

[CA1154911]

We have a DL360 file/print server which backs up every evening to a tl891dlx tape unit using dlt tapes using arcserve. Recently arcserve has been struggling with an inventory, when it finally completes it and attempts to run a backup job it can't detect the tape it's looking for even though it's in the magazine. We updated the firmware yesterday and now on teh display of the tape unit it comes up with 'fault code: 1005' 'Illegal SCSI cnt cmd'.
Any ideas?

[CA1154911]

btw, firmware version for tape drive is 05.25
Server is running 2003 with ArcServe 7.0

[CA1191018]

Michael, we are attempting to upgrade the TL891's firmware but Library and Tape Tool (LTT) couldn't do. How do you upgrade it?