A bit more experimenting, and I think this particular Vex controller is dead. The serial interface works well enough, but the PWMs don't work even with the default Vex code. It forgets the code loaded on it the instant I turn it off. That's disappointing. I might be able to get my hands on another controller later, but it looks like I'm grounded for now.
Let me know how that remote controlling goes. Interfacing with the robot through the serial port is really easy with Kevin's serial_ports.c/h code.
*yawn* it's 10:32 and I've yet to get any sleep... enough messing with this thing...