[Mark McLeod]

I'd recommend opening devices in Begin.vi and nowhere else.
I think that's your basic issue here.

What you posted has some problems, but the full answer is in all your code, not just this one piece. I'm just speculating because I'd need to see the rest of your code to positively tell you what 's wrong.

What is happening is that you are opening your drive motors in this vi, then going into an infinite loop. This vi (and only this Autonomous Independent.vi) gets killed automatically at the end of the Autonomous period. That means the Motor closes never happen by the way and they maintain the last value given them in the Autonomous loop.

I bet you try to open the motors again somewhere else (like in Begin.vi maybe?) and that leaves the motor reference in Teleop.vi invalid. You can't Open the same motor more than once.

So Autonomous leaves your motors running forever, and Teleop can't reference those same motors, as it normally should, to stop them.