Mac, the more I think about this thread and the 3 last remain brain cells of mine wake up, I kinda think there was an issue with a usb hub setup that gave problems years back, it was something about conecting thru a hub for several USB devices.
Also John, have you checked to see if you have usb driver 2.0, I had problems once when I still had usb 1.1 Hope something here sticks on the wall. Later Wyndham