I fixed it! As you predicted it wasn't the interface cable. Nor was it Windows XP. Between the last time I used the AFP software and now, I installed the Microsoft Active Sync software for my wife's palmpilot. It connects through the USB port, but the default settings in that software occupy the serial port as well. When I disabled the COM port usage for the activesync software, AFP works fine again. I'm off to fly some. I hope you and others can use this info.