Unfortunately the problem is with the graphics card. We have found that some models of the 500 series simply refuse to work in DirectX 11 mode. Sadly we have found no way around this at the moment other than to use DirectX 9 or to upgrade to a newer graphics card. As the 500 series is now a little dated it is something to consider. Plus you will get an increase in performance for only a small outlay which is always welcome.
I'm sorry I can't bring you better news.