First of all, the buttons on the drivers door do not lock/unlock the
doors that button(s) is/are situated on the central console, for universally locking
and unlocking the vehicle doors.
I had a simple problem that was caused by a seatbelt which had been incorrectly stored. I couldn't open it via the key-less system and used the button inside the car to solve it.
As you haven't included any information on what version you have it is difficult to help as I have no idea if you have key-less or normal key locking. i would you follow the guidelines and put your vehicle information in your signature (see mine for an example) then we can help you quicker.
Grand C-Max 2.0TDCI Titanium Colorado Red
Tinted windows - bi-xenon/washers - 17\" Wheels
Sony Gps SD Hands free - reversing camera - parking sensors - key free