File-level backup of virtual machine fails with "Invalid selection tree - Failed to prepare the s (81484)

Date: Dec 2008
Product & Version: All NVBU
OS Version: Windows
Module & Version: VMWare 1.0.11
Application version: N/A

Symptoms:
When using a VCB proxy, mounting an image and trying to back it up on the file-level results in the error
Error 2008/09/28 14:17:03 280 Data Plugin PROXYMACHINE Invalid selection tree
Severe Error 2008/09/28 14:17:03 280 Data Plugin PROXYMACHINE Failed to prepare the selection tree and backup options

This is a result of how the data was selected for backup. If the machine is mounted, and then ticked for backup at the level of the machine name (see attached screenshot), the backup fails as above. The workaround is to expand the machine further and ticking the individual DRIVES for backup specifically. This has been logged as fault VMW-61.