This script shows how to play audio (mp3) files in a row.

// creating a new array
var myArray:Array = new Array ();
// filling the array with audio titles
for (var i = 1; i<=3; i++) {
	myArray.push ("mp3/track"+i+".mp3");
}
var j:Number;
j = 0;
// creating a sound object
var piano:Sound = new Sound ();
// playing the first audio
piano.onLoad = function () {
	piano.start ();
};
piano.loadSound (myArray[j]);
// then playing all others
piano.onSoundComplete = function () {
	j++;
	if (j>myArray.length) {
	       trace ("stopped");
	       this.stop ();
	} else {
	       this.onLoad = function () {
	               this.start ();
	       };
	       this.loadSound (myArray[j]);
	}
};