Cannot backup Exchange Databases anymore!

Backup Exec 2010 R3 (all available updates installed) ---- For some reason after installing Exchange 2010 SP2 rollup 5 I cannot backup either the Mailbox Database or Public Folder Database. Everything else on the Exchange server backs up fine. I've exhausted all attempts to fix this. The error consistently is “: e0000391 - Backup Exec attempted to back up an Exchange database according to the job settings. The database was not found, however. Update the selection list and run the job again.”