This is supposed to fix the seatbelt getting stuck in the door, but its not a perfect fix:
1) get in seat and put on seat belt
2) there is a little plastic slider on the seat belt. Slide that so that it is up againts the male end of the seat belt
by doing that, it is supposed to keep the seat belt out of the door- something to do with keeping the metal seatbelt-thing high enough on the seatbelt strap so that its not in the door.
It works, but you have to remember to check where that slider is every once in a while, as it doesnt stay in place very well.