An attempt to take a vRanger backup of a Windows 2008 R2 machine using guest quiescing fails. (4047924)

While attempting a backup of a VMWare Hardware Version 8 machine on vSphere 5 with the "Enable Guest Quiescing" option enabled in the vRanger backup job, the attempt to take the quiesced snapshot is reported as failed in the vCenter/Host Task list. The backup fails. Inspection of the VMware task log details reveals the following errors:

The guestOS has reported an error during quiescing. The error code was: 5 The error message was: 'VMBackupOnThaw" operation failed.

The guestOS has reported an error during quiescing. The error code was: 3 The error message was: Custom quiesce script failed.

In addition, inspection of the VM's file system in the Datastore Browser reveals that snapshot files were indeed created (the presence of "*.-00000x.vmdk" files will be noted).