I have a 2000 Mitsubishi Montero Sport and have the same problem. I haven't corrected it yet but did find a way to open. I assume may work for you too.
When it sticks I usually use my thumb to push up on the inner side of the handle then press the unlock button. Works everytime for me. I think there is dirt and what not within the handle linkage.
Tuesday, September 16th, 2008 AT 6:36 PM