removing movie clip problem

I trying to load a movieclip into scene 1 and then with a close button attached to the loaded movie trying to remove the MC from scene 1. What am i doing wrong? The load works great...the unloading doesn't

attachMovie_btn.onRelease = function(){
this._parent.attachMovie("MCTrio", "trio_mc", 1);
trio_mc._x = 275;
trio_mc._y = 200;
};

and on a close button on the loaded MC i have

on (release) {
_parent.removeMovieClip("MCTrio");
}

Thanks Brian