All works fine?
Can u post the pinout of the DVD usb-connector?

If you look at my picture you can see how to modify the cable that connects to external USB cable. I could do this because I am not using the touch screen. You will have to make your own cable somehow. But the pinout should be clear from this anyway. Red and white from that cable beeing data+ and data-, and separate red and black being 5V power.

I believed that you sorted your problem with reinstallation of winxp? I guess problem came back? I am a bit confused if you still have a problem or not.

What I have seen, is that I get problem if DVD is not powered on when the PC is powered on.

Now with DVD powered together with PC (and not monitor) and not using a hub at all I have no more problems.

Good luck.