You're in luck. I've encountered this with other e-mails before. I never encountered it myself before making the tutorial 9hence why there's no clarification).

The camera itself within the movie clip that houses the box and crosshairs has to be centered itself in order for the camera to function properly.

What that means is that you have to go into the camera's movie clip and (I advise using the align toolset to do this properly) align your camera box, crosshairs and color bar so they are in the exact center of the clip (the center of a MC is distinguished by a tiny set of crosshairs that appears when you open the MC).

Make sure the box is centered (and the crosshairs if you expect them to be effective) and that the color bar is somewhere within the box, that way when the AS goes to find the dimentions for the camera (which it does constantly), and its position (also done constantly), it's not reading it off-center, and therefore capturing the image that's a little bit to the right or left or what have you.

On the other hand you could just aim the camera off center of everything you want to be viewing... but that would be illogical and quite silly...

Thanks for the review!