It's comonly known as machine gun door locks,
Do a search on this and other forums, and you will find an in depth, "how to fix the problem".
The actual fault lies within one of the actual door locks its self,and it will proberbly be a spring broken within the lock.It can be repaired if you want to save yourself some bucks.

What information you will find is, how to strip the door down, and replace the locking mechanism,
If you want to do it yourself.go for it, it's a sinch to do.
If not it's a dealer and around $300.


Or read this thread

http://www.peachparts.com/shopforum/showthread.php?t=139869

HTH