[FMX]Attached sound isn't working

Hi,

I have the following problem. I have a attachSound for three wav files in the library. This is the code:

song1 = new Sound();
song1.attachSound("song1");
song2 = new Sound();
song2.attachSound("song2");
song3 = new Sound();
song3.attachSound("song3");
song1.start();

Nothing wrong so far. When the movie starts, song1 start playing. I have a stop button with the following code:

on (release) {
 stopAllSounds();
}

This is also working.When I press the button the music stops. When I press the song1 button, song1 start playing again. But when I press on of the othet two buttons nothing happens. This is the code for the buttons:

on (release){
 _root.mc_menu.song1.start();
 _root.mc_menu.song2.stop();
 _root.mc_menu.song3.stop();
}

What am I doing wrong ?