Here's the setup: A perfectly fine maze-solver, solves mazes perfectly. I attach an XBee for experimental datalogging and extra features. I run the as-of-yet unmodified program. Robot goes nuts.

I really see no reason why this is happening. The U-MUST-BE-BLINDTM light is not messing with the line-sensors. It isn't sending anything yet. All I did was plug the NXTBee in. I'm out of ideas. The only other person who I've ever heard of using a Lineleader and a NXTBee (Spiked3) has no clue either. It's never happened to him.

Any thoughts?

No ideas?

Generic answers; try a different brick, heck try different batteries. Mount the xbee somewhere else. Drop back to robotc 3.08. swap radios attached to the NXBee.

If these all fail and you get no closer, welcome to my world.

What light sensors are you using? I'm guessing that the XBee probably takes a nice bit of power to run, so maybe your light sensors aren't getting the power they need to function reliably.

If you have a volt meter, measure the sensor supply voltage with and without the NXTBee connected (the supply voltage uses pins 2 and 3 for Gnd, and 4 for 4.3-4.7v). The sensor supply voltage should never go below 4 volts.

I'm using the original Mindsensor LineLeader. I will try that.