Help pls. (mp3 using flash)

Im not really familiar with adobe flash and especially coding.so pls bear with me T.T

i managed to search for a working code for pause/start/play buttons for my mp3.

here is the code:

stop();

var mySound:Sound;

var myChannel:SoundChannel;

var soundIsPlaying:Boolean = false; //prevent play btn overlap

var p:uint = 0;

mySound = new Sound;

mySound.load(new URLRequest("Fall Out Boy - Beat It ft. John Mayer.mp3"));

btn_play.addEventListener(MouseEvent.CLICK, playSound);

btn_stop.addEventListener(MouseEvent.CLICK, stopSound);

btn_pause.addEventListener(MouseEvent.CLICK, pauseSound);

function stopSound(myEvent:MouseEvent):void {

myChannel.stop();

p = 0;

soundIsPlaying = false;

}

function playSound(myEvent:MouseEvent):void {

if (!soundIsPlaying) {

myChannel = mySound.play(p); //play song location (p)

soundIsPlaying = true;

  }

}

function pauseSound(myEvent:MouseEvent):void {

if (soundIsPlaying) {

p = Math.floor(myChannel.position);

myChannel.stop();

soundIsPlaying = false;

}

}

//prev and next buttons//

btn_next.addEventListener(MouseEvent.CLICK, MightWork);

function MightWork(event:MouseEvent):void

{

  nextFrame();

}

btn_prev.addEventListener(MouseEvent.CLICK, MightNot);

function MightNot(event:MouseEvent):void

{

  prevFrame();

}

im going to make five frames, with five different songs on the action script. but when i press previous or next button. my songs would overlap each other...

"SoundMixer.stopAll()" wont work for me... pls help.