ActionScript 3.0 :: Show MovieClip With Keypress Not Working

I am trying to make an interactive presentation, where you can push down on different keys and show different layers in my image. [URL]. If you open this .swf and press the "Q,W,E,R,T" keys you can see what I mean. It was working fine with the layers associated with the "Q W E" keys, but once I started adding more, I cannot press and reveal more than 3 layers at once (try pressing different combinations of three keys at once and you should see that not all of the layers appear, but each key works individually).

Here is my AS3:
Code:
import caurina.transitions.*;
mc_aerial.alpha = 0;
mc_01.alpha = 0;
mc_02.alpha = 0;
mc_03.alpha = 0;
mc_04.alpha = 0;
stage.addEventListener(KeyboardEvent.KEY_DOWN, mc_aerial_KeyDown);
function mc_aerial_KeyDown (e:KeyboardEvent):void{
[Code] .....