i think the car comes from the factory with that feature activated. did yours get disabled?

if your car door is open, you cannot lock the doors because there's a chance the keys could get stuck in the car. if the doors are closed when you push the lock button, then it sounds like you have a different problem. do the door lock pins (on top of the door panel) ever go down or are the always stuck up? ie. when you lock the car with the key fob, etc.