NT Backup fails to run sporadically W2K3-R2

[Peter]

I have a strange problem with a server that I recently upgraded
(installed from scratch - NOT in-place upgrade) from Windows 2000
server to Windows 2003-R3(SP2) server

I use NTBackup for nightly tape backup and sometimes it just doesn't
run at all. There doesn't *seem* to be a pattern. There's no error
mesage - it just doesn't run. BUT - if I run it manually it never
fails.

Here's the relevant hardware config:

.. IBM 226 Server
.. AIC7902B Ultra 320 SCSI
.. Sony AIT 50 GB SCSI Drive on Bus Number 0, Target ID 0, LUN 0 -
Driver version is "1.0.0.4" (31/08/2004)

My backup batch file is
rsm refresh /lf"Sony AIT 50 GB SCSI Drive"
c:\batch\Sleep 30
C:\WINDOWS\system32\ntbackup.exe backup "@C:\Documents and Settings
\Administrator.DOMAIN\Local Settings\Application Data\Microsoft
\Windows NT\NTBackup\data\backup.bks" /n "Backup Media" /d "Backup
Set" /v:no /r:no /rs:no /hcn /m normal /j "server1" /l:s /p "8mm
AIT1" /um

Note:....
rsm refresh /lf"Sony AIT 50 GB SCSI Drive" sometimes displays:
No match was found for the friendly name supplied.
Unable to convert library friendly name to guid.

Even though....
RSM VIEW /TLIBRARY always shows:
Off-line Media
HL-DT-ST CD-ROM GCR-8482B
Sony AIT 50 GB SCSI Drive


I just need to guarantee that backup will run reliably overnight. Any
suggestions?