I have experienced 2 system crashes recently on our SBS 2003 server. After looking through the minidump files it appears that the SCSIPORT.SYS driver is the cause. I have gone through numerous microsoft support articles but all relate to an older version of the driver and it appears that this should have been corrected with the install of service pack 1, we currently have service pack 2 installed.
After going through the event log it appears that the system crash happens immediately after the Symantec Backup Exec finishes its nightly backup. I have also checked and the drivers and the firmware for the 2 tape drives are up to date.
I have also posted the minidump files for your review.