My first actionscript command: gotoAndPlay is not working

Hi everyone,
This is my first actionscript command and it is not working.
The first layer of the clip is some music which doesn’t stop during the whole
clip. I want to change scenes while the music plays so i add another layer
and in frame 20 i add an action the says:

gotoAndPlay("scene 2",1);

The script ignores that code and continues playing the music at scene 1.
Any idea why ? Is there a way to go from one scene to another while the same
music plays?
Thanks !

Only if you play your sound via actionscript, not in a timeline.

Could you show me how to activate an mp3 file via Actionscript?
Thank you