Backups failed with " Unknown Error has occured"

HI.. I have just installed Backup Exec 11d and all was going well until last week when backups were failing but not every day. The link takes me to a Symantec support page (http://eventlookup.veritas.com/eventlookup/EventLookup.jhtml?EvtID=V-79-57344-34036 ) that tells me to run the services with a domain admin account. This is the case but they still fail.

 

Has anyone come accross this issue?

 

Thanks

Paul