Help on actionscript

im using this actionscript code to generate fire effect on my flash ad but i want this code to disable in a frame when the ad plays, can you pls help me on this.

function mover(){
this._y += this.speed;
}
function fire(x1,n){
for(i = 0; i<n; i++){
path = this.createEmptyMovieClip(“path”+i, i);
path._x = Math.random()x1;
path.startFrame = 2
Math.abs(25 - path._x);
dot = this.path.attachMovie(“flame”, “flame”, 0);
dot.speed = -(Math.random()*5+1);
dot.gotoAndPlay(Math.round(Math.random()*34));
dot.onEnterFrame= mover;
}
}
fire(600, 725);