UnloadMovie problem

hi -
I have a movieclip where a movie is being loaded and which can be closed via a close button. This works fine with the following script:

var quiz = this.createEmptyMovieClip("quiz", this.getNextHighestDepth());
quiz.loadMovie("quiz.swf");

closed.onPress = function(){

unloadMovie(quiz)
}

But when the movie is loaded (and the close button has not been pressed) and I click on a button on the root this movie is still visible.
I tried it with this script on the button on the root.

animation.unloadMovie(quiz);

It didn’t work. Can anyone please help?