Sound not loading

Question

I have the following code:
myVars = new LoadVars();
myVars.load("http://charlesnewmanpubl.com/Sweethearts_On_Parade_BRGK.txt");
myVars.onData = function(src){
     myVars.decode(src)
     //trace(myVars.faFile);
     var faFile:String;
     var sound : Sound;
     if (myVars.faFile == undefined) {
        trace("not yet.");
    } else {
        faFile = myVars.faFile;
        trace(faFile + "!");//so far so good
        this.sound.loadSound("http://charlesnewmanpubl.com/media/"+faFile,true);
        clearInterval(param_interval);
     trace(faFile + "!!");//we're ok here
     this.sound.onLoad = function(success:Boolean) {//this is where it's failing
        trace(faFile + "!!!");//nada
        if (success) {
         this.playing = true
         this.sound.start (this.sound.soundIndex / 1000)
            trace("Sound loaded");//not here
     }else{
         trace("Sound failed");//or here
This is a loadVars of a .txt, one variable of which is the name of a .mp3 file. I test to see if we've gotten all the data from the .txt, and then what the variable "faFile" is. That's then checked twice, both successfully. But when it gets to the section of whether the sound has actually loaded, and then should play, there's no reposrt.
So I'm not loading the .mp3, but don't understand why.

Answer 1

try: 
myVars = new LoadVars();
var sound : Sound;
myVars.onData = function(src){
     myVars.decode(src)
     //trace(myVars.faFile);
     var faFile:String;
     if (myVars.faFile == undefined) {
        trace("not yet.");
    } else {
        faFile = myVars.faFile;
        trace(faFile + "!");//so far so good
        sound.loadSound("http://charlesnewmanpubl.com/media/"+faFile,true);
        //clearInterval(param_interval);
     trace(faFile + "!!");//we're ok here
sound.onLoad = function(success:Boolean) {//this is where it's failing
        trace(faFile + "!!!");//nada
        if (success) {
         this.playing = true
         this.sound.start (this.sound.soundIndex / 1000)
            trace("Sound loaded");//not here
     }else{
         trace("Sound failed");//or here
myVars.load("http://charlesnewmanpubl.com/Sweethearts_On_Parade_BRGK.txt");