Backup and restore

I'm trying to streamline the backup process for our servers, so I set one machine to backup to a Samba share as a test.

Although the files do appear to be backed up properly, the backup function reports an error in both the backup log and in the emailed backup report.

I remember something similar happening when I tried to backup to an AFP share from one of the Mac servers a while back, but never had time to investigate it further.

Any idea of what might be going on here?