Generally any time that I have seen that message, either a disconnect/reconnect of the USBTAP from the USB port or shutting down and restarting CodeWarrior generally seems to fix it. Even if the driver that interfaces Codewarrior <-> USBTAP was locked up I would expect that the rebooting of the PC would correct. Perhaps your USBTAP has suffered a hardware failure ? What do you observe for LED activity on the USBTAP when it is connected to the PC alone, to the target board, and when you try to download or connect to the target board ? Perhaps this information might provide more clues.