I have VDP 5.1.11.3 installed and backing up a mix of Windows and Linux VMs across two ESXi 5.1 Update 1. The VMs are backing up properly and I have recent mount points available, however, when I log into the FLR client on a Windows Server 2003 guest VM, mount and mount a backup, I see no files that I can restore. I have the same symptoms when attempting to use the FLR client on a different Windows Server 2008 R2 VM. I have checked dozens of mounted backups and all show no files available for restore.
Both VMs in question have a single virtual disk, no special partitioning configuration, MBR-type partition tables and only Windows basic disk types.
See below for a screenshot of the symptom I'm experiencing.