you should have:
import flash.events.MouseEvent;
import flash.events.Event;
stop();
var myChannel:SoundChannel;
var mySound:Sound=new Sound();
listenMe();
prev_btn.visible=false;
next_btn.addEventListener(MouseEvent.CLICK, clickNext);
prev_btn.addEventListener(MouseEvent.CLICK, clickPrev);
function clickNext(e:MouseEvent):void {
nextFrame();
listenMe();
}
function clickPrev(e:MouseEvent):void {
prevFrame();
listenMe();
}
function listenMe():void {
var C:Class=Class(getDefinitionByName("Audio_"+this.currentFrame);
mySound=new C();
myChannel=mySound.play()
prev_btn.visible=next_btn.visible=true;
if (currentFrame == 1) {
prev_btn.visible = false;
} else if (currentFrame == totalFrames) {
next_btn.visible = false;
}
}