This is a door actuator problem. I had the same thing happen to me except all the doors were locked. I had to go dukes of hazard style into the car. The solution I used was to change the 15 amp fuse to a 20 amp according to this thread: http://www.m3post.com/forums/showthread.php?t=454441
worked like a charm. Brought to dealer recently and told them about it in case they need to change actuator or something and they told me that I did exactly what they would have done!
Save yourself trip to dealer. buy a fuse.