Backup server reboots automatically

Trying to backup vm servers that have Windows 2008 R2 Enterprise installed on them.  When I start the backup job, it looks to be running ok but after 30-50 minutes into the job, the backup server using Backup Exec 2010 R3 and Windows 2003 Standard SP2 reboots automatically.  Checked the Windows event log and not seeing any help for this and no alerts in the Backup Exec.  I have not noticed the automatic rebooting of the server that runs backup exec when I try to backup the servers running Windows 2003.  Is this an issue with Backup Exec 2010 R3 trying to backup Windows 2008 R2 machine?