Is it possible to have 2 classes of backups?

So close, yet so far…

It appears the two machines I’ve setup like this are running full backups over and over. But when I look in the logs, I get:

Errors 07.05.14 09:54 FATAL: Error writing to VHD-File.
Errors 07.05.14 09:54 FATAL ERROR: Could not write to VHD-File
Errors 07.05.14 09:54 Backup failed

Machine1: Windows 8.1
Machine2: Windows 7

Nothing special beyond that – but same result for each.

Not sure where to go from here…