When you attempt to run Real Race, is your G2 USB controller still plugged in? If so, try unplugging the G2 controller first, before booting up the Real Race software.

Well, I just tried mine and it works fine. I did not have my Real Flight USB controller plugged in but my car race controller is plugged in and has been for a long time. Also, I have Real Race G2 version if that makes a difference.

Hope this helps and you get yours figured out!