We are having similar issues with the backups, what do you mean by having the same owner? does it mean the same user that created the backup specifications? Its working fine on our file level backups but doing full backups instead of inc on all the VM's.
[Warning] From: VEPALIB_VMWARE@domainname"/CEN" Time: 1/17/2014 11:00:20 AM
Virtual Machine 'XXXDEVF0332K801': Could not find valid previous backup ...
[Warning] From: VEPALIB_VMWARE@domainname"/CEN" Time: 1/17/2014 11:00:20 AM
[172:151] Virtual machine 'XXXDEVF0332K801': Incremental/Differential backup not enabled.