Benz916

I just had an engine light come on a few days ago. Its P0100. I belive its the air flow meter but i just changed it this past jan. COuld it have messed up again? It was brand new. A few weeks ago...i ran the car low on gas..maybe even fumes...so i filled it up and the next day the gauge read empty and then eventually started working, but thats when my engine check light came on. The car will start, but at idle it wants to die. This may sound a lil wierd, but the last time i ran low on fuel, the engine check light came on and it was the air flow meter. COuld there be any correlation? What does p0100 mean...help guys.