Backup system fail since conversion to 2012

We upgraded Backup Exec 2010 R3 to 2012 last week and after recreating every backup job for every server, I've been having issues with the backup of the System State on the server with Backup Exec installed on.

Everynight I get an error that COM+ REGDB is corrupted and twice that WMI was corrupted (once last week and last night)

I ran a chkdsk last week-end and except for a few minor inconsistencies in the index, it did not find anything wrong.

I was told to try NTBackup and it doesn't encounter any errors.

Any idea what I can try to fix this problem?

Thank you