Flash lecteur MP3 va un peu détraqué

 
var playing:Boolean = false;
var pausePoint:Number = 0;
 
stopbutton.addEventListener(MouseEvent.CLICK, stopButtonClick);
 
function stopButtonClick(event:MouseEvent):void {
    theChannel.stop();
    pausepoint = 0;
 
 
}
 
 
 
playpause_button.addEventListener(MouseEvent.CLICK, playpauseButtonClick);
function playpauseButtonClick(event:MouseEvent):void {
    playing = playing ? false : true;
    if (playing) {
 
        theChannel = theSound.play(pausePoint);
    } else {
 
        pausePoint = theChannel.position;
        theChannel.stop();
    }
}
 
prev_button.addEventListener(MouseEvent.CLICK, prevButtonClick);
 
function prevButtonClick(event:MouseEvent):void {
 
    if (b > 1) {
        b = b - 1;
        theChannel.stop();
        gotoAndPlay("startTrack");
    } else {
        b = this.totalfiles;
        theChannel.stop();
        gotoAndPlay("startTrack");
    }
}
 
 
next_button.addEventListener(MouseEvent.CLICK, nextButtonClick);
 
function nextButtonClick(event:MouseEvent):void {
 
    if (b < this.totalfiles) {
        b = b + 1;
        theChannel.stop();
        gotoAndPlay("startTrack");
    } else {
        b = 1;
        theChannel.stop();
        gotoAndPlay("startTrack");
    }
}