How come it works in MX pro and doesn´t in MX?

Im using this as for two buttons, pause and play:

//this is the pause button
on (press) {
_root.myMusicPosition = _root.sonido1.position/1000; _root.sonido1.stop(); sonido1 = new Sound(photo);

//this is the play button
on (press) {
[/AS]It works ok in Flash MX pro, but doesn´t work in the MX.
Does somebody know why?

Tanks! :stuck_out_tongue: