Don'y know if you are still following this thread, but . . . I had exactly the same problem. Drove me nuts. I just called Mad Dog. (Only 4 minutes on hold.) Nice man told me to take disc out of drive, turn off drive, unplug USB cable, wait 10 seconds, plug cable back in, turn drive back on. And IT WORKED! Simple as that. (I suspect you really do not have to disconnect USB cable.)
He hinted that the drive has problems when turned on with certain discs in drive, but he would not elaborate. Anyway, works for me. I suspect you have solved problem by now.