You don't have the appropriate ASPI driver loaded.
NWASPI is rather generic and does not have any tape device support
built in. Loading your SCSI controller will attempt to autoload
NWTAPE.CDM, but you should not use it. It is designed for Novell's
SBACKUP and will interfere with BE. BECDM (custom ASPI manager from
Veritas) will give you ASPI interface with the needed tape device

If you're running BE8.5 you should be using NWASPI (though there's a
way to make BECDM work w/8.5) and you should NOT have NWTAPE running.
Rename or delete it altogether.