Server rebooting - infrequent, but annoying

I have an HP ProLiant DL380 G4 that has been rebooting.  Running Windows 2003 SP2, fully patched as of 11-2-08.  Reboots always happen in the early morning during full backups (ca ArcServe).  Not Data Center or power related - it's in a well protected, secured, temp controlled Data Center - 50 other servers running just fine.

Happened on following dates:
2/24/08
2/27/08
4/2/08
5/4/08

Then as troubleshooting measure, on 5/12/08 I installed MS KB937455 hotfix - NTFS File system Hotfix.  Everything was great until 9/25/08.  Now it's rebooted 3 of last 4 Friday's during backup.

Here is the stop code that I get:
Event Type:      Information
Event Source:      Save Dump
Event Category:      None
Event ID:      1001
Date:            11/1/2008
Time:            8:36:54 AM
User:            N/A
Computer:      FILESRV01
Description:
The computer has rebooted from a bugcheck.
The bugcheck was: 0x000000e1 (0x80920183, 0x00000001, 0x00000000, 0x808ad390).
A dump was saved in: C:\WINDOWS\MEMORY.DMP.

Should I try re-applying KB937455?  Maybe one of the other "normal" security patches had a negative impact on the original install?

Anyone have any other suggestions?  I've talked to HP, but of course they say it's an OS issue.  I'm thinking along the lines of a NIC driver, or NIC Teaming driver that might be the cause.

Thanks,
Tim