The reason for the error is because if you don't service or poll the usbservice very quickly at startup, it will have an issue. I bet if you looked at your program, it takes longer then 10mS to get to the point where usbservice is included. I believe, and someone with more USB experience then me can correct me if I am wrong, that once the device is enumerated, there can be a longer delay but on startup it must be quick. This post was over a year ago and I haven't corrected the root of the problem. With that small snippet in my code, the device works fine. I guess I have the saying, "If it aint' broke, don't fix it!" Sorry I can't help any further.