Here is a little "bug fix" for you , so i can be a bit usefull to you , as you ve been to me.
get a number var called test

var test:Number=0;

then add in pauseSong function the below line

test=1;

and change playSong function to

function playSong(e:Event):void {
if (test==1) {
test=0;
sc=currentSound.play(CurrentPos);


}
}

This should fix a little bug that exists when you press play button while a song already is being played.