Differential backup of template VMs will fail with a similar error:
2012-07-31 11:39:00.779]: Backup failed: An internal error occurred during execution, please contact Quest support if the error persists. Error Message: 3201 - can't open [Hitatchi_Hyperion-Test_Datastore_44] Rchits01/Rchits01.vmdk
Also will see error: Template Diff Backup fails with error Unable to continue Differential backup; the vRanger snapshot was not found.
This defect was logged in version 5.4 but was found in as early as 5.3.
Please upgrade to latest vRanger version 5.5 if experiencing this issue.
Upgrade located here:
https://support.quest.com/SoftwareDownloads.aspx?ProductID=268446589&ProductName=vRanger
