Does your deck lid lock?
How about your gas filler door?
If all those work then chances are its a leak somewhere in the front of the car. If none of your locks work the pump either has a major leak or its shot.
I had a similar issue with my deck lid and gas filler door and it was one of the pneumatic lines. I had the dealer fix it because I didn't feel like tearing the interior apart. If there is a leak you should be able to hear it. Hit the lock and you should hear a hissing sound. I think 180 is right on the money, I concur with his assessment of the problem. Let us know how you make out.