I don't know the "hwinterface.sys", so I can't comment on that particular problem. However when you report a bug here it would be good to know which version you are using, and also the content of the acklog.txt when you encounter such a problem and start with -diag. The acklog.txt also gives you a hint when something goes wrong. Maybe its not related to the "hwinterface.sys" but to something simple, like an empty level or a wrong camera position.