attachMovie Problem!

programming flash
1

I have a little game I’m making for school, and one of my attachMovie lines is not working. I added a line to test if the movieClip is was attached and it returns NULL. I have tried everything in my knowledge and need help please.

This is the code to fire the bullet:


function onMouseDown() {
    h++;
    angle = turret._rotation-1;
    bullet_x = turret._x+48*Math.cos(angle*Math.PI/180);
    bullet_y = turret._y+48*Math.sin(angle*Math.PI/180);
    var bulletN = "bullet"+h;
    _root.attachMovie("bullet", bulletN, _root.getNextHighestDepth(), {_x:bullet_x, _y:bullet_y});
    if (_root[bulletN] == NULL) {
        trace("The bullet wasn't created!");
    }
    _root[bulletN].dirx = Math.cos(angle*Math.PI/180)*firepower;
    _root[bulletN].diry = Math.sin(angle*Math.PI/180)*firepower;
    _root[bulletN].onEnterFrame = function() {
        this._x += 50;
        this._y += 50;
    };
}

My hunch is something is wrong with this line:

_root.attachMovie("bullet", bulletN, _root.getNextHighestDepth(), {_x:bullet_x, _y:bullet_y});

Any help is welcome! Thanks!