The locks on ours were a bit loose when new, too Brad. But I just tweaked the latching bar behind the lock with a couple of pliers until it grabbed better. Just be careful not to overdo it and crack some fiberglass. The bumper inside was part of the problem also, but it too can be aligned and tweaked until the door is just snugged a bit (doesn't rattle) with the key latch, but not so tight as to cause other problems.
Joel