Backupper is really nice compact software, but:
First "New Backup" use credentials from "NAS browser", and it is correct.
"Check Image" use same credentials, so ok.
Next backup of this task use GUEST account
I suppose your problem is the same as this post: http://www.disk-partition.com/forum/discussion/352/backupper-standard-2-0-scheduled-backup-requires-manual-username-password-entry If so, could you allow us to do remote assistance?
Best Regards,KimAOMEI Support Team