Debugging a crashed Flash application

What is the best way to debug a CRASHING flash application? (no exception, my app just crashes) I'm really running into a big problem: my app (fully functional website) works fine with flashplayer 9, but crashes with flashplayer 10 ...

Here is a BAD method that crashed my application using FP10. After removing the call to this method, everything worked correctly with FP10.

public static function drawWedgeCrown(g : Graphics,a : Number,r : Number,r2 : Number, n : Number, c : Number, t : Number) : void {
            var x : Number ;
            var y : Number;               
            g.beginFill(c, t);
            g.moveTo(r, 0);
            g.lineTo(r, 0);
            var teta : Number = 0;
            var dteta : Number = 2 * Math.PI / n;
            while(teta < a) {
                x = r * Math.cos(teta);
                y = -r * Math.sin(teta);
                g.lineTo(x, y);
                teta += dteta;
            }
            x = r * Math.cos(a);
            y = -r * Math.sin(a);
            g.lineTo(x, y);           
            x = r2 * Math.cos(a);
            y = -r2 * Math.sin(a);
            g.lineTo(x, y);
            teta = a;
            dteta = 2 * Math.PI / n;
            var cpt : int = 0;           
            while(teta > 0) {
                cpt++;
                x = r2 * Math.cos(teta);
                y = -r2 * Math.sin(teta);
                g.lineTo(x, y);                           
                teta -= dteta;
            }
            x = r2 * Math.cos(0);
            y = -r2 * Math.sin(0);
            g.lineTo(x, y);
            g.lineTo(r, 0);           
            g.endFill();
        }

      

        
        
        
      

    

OK, I finally found the real PROBLEM ... this was not the method he used himself. I was passing NaN for argument "A" causing an infinite loop ...