After reading the ambiguous veritas error code trouble shooting tips on line I realized they all mentioned VSS, but didn't really have a quick fix for the problem. So, I tinkered around and found the following to work pretty much 99% of the time.
Of course, you'll want to validate your configurations as the 1st step of trouble shooting.
In most cases simply starting and stoping the Microsoft Volume Shadow Copy Service solved the problem, which should be set to manual Start type.
Otherwise, I make sure my the client attributes are set to the settings listed below.
Windows Open File Backup Configurations on Host Server > Client Attributes
-Enable Windows Open File Backups for this Client
-Use Microsoft Volume Shadow Copy Service VSS
-Global drive snapshots
-Disable Snapshots & continue
Physical and Virtual Servers
Windows 2003 and 2008 r2
Veritas Netbackup Client 6.5 and 7.1