[1508] 02/13/13 13:32:41.375 DeviceIo: 04:00:17:00 - Device error 1117 on "\\.\Tape0", SCSI cmd b5, 6 total errors
SCSI: Raw CDB
SCSI: B5 20 00 10 00 00 00 00 00 34 00 00 . .......4..
SCSI:
SCSI: CDB Operation SECURITY_PROTOCOL_OUT
Your issue seems to be triggered by the B5 SCSI command, which is related to encryption.
Are you using encryption? If so, is it hardware or software encryption?
Is your IBM LTO4 drive stand-alone or is it in a robotic library/changer?
Are you using LTO3 or LTO4 media?
You stated that you used to be able to catalog and/or restore previously. do you know what might have changed since then?