labview interface for arduino

my project is to turn on a LED (Pin 13) while I'm pressing a button with my x-box controller.

my board is on a (robot chassis with two wheels which is fixed with two electro-motors).

i have installed the toolkit labview interface for arduino. then I've upload the sketch calls LVIFA_Base into my arduino uno board.

I followed this video http://www.youtube.com/watch?v=RGRhIQneO6w but i modify the project instead of the boolean button I use my controller to turn on the LED on Pin 13.

That works only if i connect just the board (without the motorshield "ardumoto").

The second part is to stack a motordriver "ardumoto" on the pins of the uno board. I connect the motorshield with the two electromotors and stack the motorshield on my board. The problem is that the wheels begin to drive. What's the reason?

I want to control the wheels with my controller and not automatically :0