"An error occurred while quiescing the virtual machine." (4036448)

"An error occurred while quiescing the virtual machine."

When vRanger tries to take a snapshot it fails with the following message: "Error: API Call failed with message: An error occurred while quiescing the virtual machine. See the virtual machine's event log for details." The vSphere logs state: The guest OS has reported an error during quiescing. The error code was: 5 The error message was: 'VmBackupOnFreeze' operation failed. The guest OS has reported an error during quiescing. The error code was: 2 The error message was: Custom quiesce script failed.