I'm sorry to say that I'm not finding anything on this error related to virtual disks. If you are able to mount the virtual disk, which appears to be the case, I'd suggest running a Windows scan of the virtual disk, with the hope that there is something it can correct.
While this may have been caused by using a nonsupported operating system (the release notes that are presented when installing the software indicate what supporting systems, as well as much other important considerations should always be read), it might have been caused by something else. Virtual disks with important data can be backed up by copying the pqd container file to another safe location.
The frustration of not yet having Windows 8 support is understood, and is being worked on.