Sorry to hi-jack, but my drivers door suffers a similar problem however I can unlock it (every time so far) but putting the key in and manually unlocking it. Quite amusing when I do that without using the remote and the alarm decides to go off... Real good look when I'm in trackies and have a cap on stood next to a sport hatchback screaming in fear.
Anyway, is it worth changing locks or should I just leave it as to be honest, I don't want to mess with something like door locks unless I need to...