Does one of these help you, Abe?
(1) Your Profile "Products" info shows " MacBook Pro, Mac OS X (10.4.1) ". If this is correct, you may be using an early MBP and/or display. Have you checked for the firmware update? http://support.apple.com/kb/HT3957
(2) Consider Apple's suggestions from the "If the built-in iSight camera, microphone, speakers, or USB ports on the display are not working:" section of http://support.apple.com/kb/TS2400
(3) If you are using a non-Apple external display, contact the seller or manufacturer for help.