Servomotor wont move at all (Knock Lock Project 12)

We are having trouble with the knock lock project in the Arduino's projects book. Our servomotor is not working or moving at all. We believe that everything is set up correctly and the code was compiled. Are there any other factors to keep in mind in regards to issues with the servo motor?

Have you tested the servo with the sweep sketch?

We aren't all familiar with the projects book so don't necessarily know the circuit and sketch: might be an idea to post those for all to see.

Hope the servo's not powered from the Arduino. Assuming it isn't are the grounds all hooked up together?