Preloader for a movie

hi .

i tried to load an image into my stage. with clicking a button

so i put actionscript for the button as such :

on (release) {

    loadMovie("folderir.jpg", _root.loader.photo);
	l = this.getBytesLoaded();
	t = this.getBytesTotal();
	load_text.text = Math.floor((l/t)*100);
	load_text.text = percentage ;
	load_text.text;
	if (percentage >= 100) {
		

		_root.loader._x = 11;
		_root.loader._y = 15;
		load_text.text = "";

}

but the loader is not working the % which has to count to 100 then show the picture
doesnt work and the picture appears with out loading…

could u help me with that ?

p.s : i have load_text under property of dynamic text with its instance name.