Pixel text effect does not runs well

programming flash
1

I’ve try to practice a tutorial in this page


but when I try to run it, when I moue over the text, the text behind doesnot appear correctly.

So, I try to check my code and I found this:

this.bmd = new BitmapData(this.rects.right, this.rects.bottom, true, 0);    
bmd.draw(this.letters);    
for(this.i=this.rects.left; this.i<this.rects.right; i++){            
        for(this.j=this.rects.top; this.j<this.rects.bottom; j++){
            this.pixelValue = this.bmd.getPixel32(this.i,this.j); >>> return 0
            this.alphaValue = this.pixelValue >> 24 & 255;                
            if(this.pixelValue != 0){
                this.positions.push({xpos:this.i, ypos:this.j, alpha:(this.alphaValue/255)*1});
            }            
        }
    }

How can I resolve this? or Is there any wrong code that I’ve made?
NB: this the fla file

-Thanks-