Well, I had to re-install CS5.5 because CS6 sucks dick. I been fucking with this platformer tutorial for the most of the night and it's not easy. Lots of confusing things, I'll have to go through it and try to study some of it. Some piece of code that I did understand --

//This is just telling the computer when the arrow keys are being pressed down.
function keyDownHandler(e:KeyboardEvent):void{
if(e.keyCode == Keyboard.LEFT){
leftPressed = true;
} else if(e.keyCode == Keyboard.RIGHT){
rightPressed = true;
} else if(e.keyCode == Keyboard.UP){
upPressed = true;
} else if(e.keyCode == Keyboard.DOWN){
downPressed = true;
}
}