reading
http://www.kevin.org/frc/CMUcam2_workbook.pdf may help.
A few things to note (some basic things I skimmed over):
to run the camera you need a charged backup battery (although if its not charged the camera's likely not turning on)
calibration is needed in rare cases (extreme lighting, if using kevins code)
and last questions, have you changed kevin's code? if you have, did you try it unmodified? and have you tried easyC, as the name suggests it is easy to learn, its what I am teaching programming on, and use to quickly prototype.
EDIT: Seems Alan beat me to it