Adding objects to an array Problem

programming flash
1

I’m having trouble with my code. I keep getting this error

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at Test_fla::MainTimeline/frame1()

I believe it has something to do with the array, considering it works when I remove the array stuff. What i’m trying to do is to be able to move objects through an array with my gravitate() function in the Grav Class.

Any help would be greatly appreciated

stage.addEventListener(Event.ENTER_FRAME,onLoop, false, 0, true);

for(var i:uint=0; i < numParticles; i++){

var p:Grav = new Grav(5, 0xff0000, Math.random()*250, Math.random()*250);
addChild§;
particles.push§;
}

function onLoop(evt:Event):void {

//for(var i:uint=0; i < numParticles; i++){
//particles*.gravitate(1,1);
//}

}