The reason is not working for you because you are using BetaQuasi VMDK file?
Instead of VMDK, change to PLOP - Boot to unRAID USB via PLOP unRAID Guest. See information here http://lime-technology.com/forum/index.php?topic=40679.0
The advantage of using PLOP is you can use unRAIDs (v6) built in OS Update.
If I were you, I would take a take a screenshot of your webGui Main page and Make a backup of your USB Flash device.
Then format your USB, use PLOP VM and fresh unRAID 6 install.