attachMovie _level problem

programming flash
1

hi folks i got a problem with a mc which i would like to attach.
heres my script;

loadMovieNum('dar/0.jpg', 5);
onEnterFrame = function() {
	trace(_level5);
	if(_level5.getBytesLoaded() == _level5.getBytesTotal()) {
// not working
		_level5.attachMovie('sound_mc', 'snd_mc', 1);
		_level5.snd_mc.onEnterFrame = function() {
			trace(this._x);
		}
// working
		delete this.onEnterFrame;
	}
}

i would be very glad if somebody could help me…