I just purchased the 328 board motor shield. I'm using instructions from here: Using Stepper Motors | Adafruit Motor Shield | Adafruit Learning System
When I put on the shield and try to run the code given, it will load once. When I try to plug the stepper motor in, it just doesn't work (except for a little tiny motion when I plug it in for the first time). The voltage on the servo 1/2 is about .3-.4 V.
Additionally, when I try to re-upload new code, it says that it can't, and I have to change the COM port or plug/unplug the arduino if I want it to be able to properly change code.
What is going wrong and how do I fix it?