oh wow!!! i had that problem when i first got my truck --- i sprayed the crap out of the sensors in the door jam with WD40. it had alot of dirt and grease on it. after jackin with it for about 20 min (spraying, cleanin, openin and shutting the door) it finally went away --- yay.
now watch -- as soon as i say that -- its going to come back and haunt me