It seems that the backup fails to trigger the VM snapshots, whether the CBT is on or off.
The host machine is a Windows Server 2012R2
1 Guest is the same (2012R2)
The other guest is Ubuntu 32 bits.
VMware guest machines package is installed.
It seems the reason is that the guest is not ready for backup now.
Due to the fact that CloudBerry Backup turns to VMWare to create the snapshots and then backs up those, the issue should be resolved with your VMWare administrator.