Init();/addChild issues

1

[COLOR=#000000][FONT=Arial]hey im doing the “Flash Bubbles: Paricle Systems with TimelineMax” from youtube. i got this code:[/FONT][/COLOR]
[COLOR=#00008B]package[/COLOR]
{
[COLOR=#00008B]import[/COLOR] com.greensock.;
[COLOR=#00008B]import[/COLOR] com.greensock.easing.;
[COLOR=#00008B]import[/COLOR] flash.display.[COLOR=#2B91AF]MovieClip[/COLOR];
[COLOR=#00008B]import[/COLOR] flash.display.[COLOR=#2B91AF]Sprite[/COLOR];
[COLOR=#00008B]import[/COLOR] flash.events.[COLOR=#2B91AF]Event[/COLOR];
[COLOR=#00008B]import[/COLOR] flash.events.[COLOR=#2B91AF]MouseEvent[/COLOR];

[COLOR=#00008B]public[/COLOR] [COLOR=#00008B]class[/COLOR] main [COLOR=#00008B]extends[/COLOR] [COLOR=#2B91AF]Sprite[/COLOR]
{
[COLOR=#00008B]private[/COLOR] [COLOR=#00008B]var[/COLOR] BG:bg= [COLOR=#00008B]new[/COLOR] bg;
[COLOR=#00008B]private[/COLOR] [COLOR=#00008B]var[/COLOR] start_btn:start_button= [COLOR=#00008B]new[/COLOR] start_button;

[COLOR=#00008B]private[/COLOR]  [COLOR=#00008B]var[/COLOR] tl:[COLOR=#2B91AF]TimelineMax[/COLOR]= [COLOR=#00008B]new[/COLOR] [COLOR=#2B91AF]TimelineMax[/COLOR]();
[COLOR=#00008B]private[/COLOR] [COLOR=#00008B]var[/COLOR] bubbleMax:[COLOR=#2B91AF]Number[/COLOR] = [COLOR=#800000]50[/COLOR];


[COLOR=#00008B]public[/COLOR] [COLOR=#00008B]function[/COLOR] main()
{
    stage.addChild(BG);
    stage.addChild(start_btn);

    BG.y= (stage.stageWidth)/[COLOR=#800000]2[/COLOR];
    BG.x = (stage.stageWidth)/[COLOR=#800000]2[/COLOR];
    start_btn.x = (stage.stageWidth)/[COLOR=#800000]2[/COLOR];
    start_btn.y = (stage.stageHeight)/[COLOR=#800000]2[/COLOR];
    start_btn.addEventListener([COLOR=#2B91AF]MouseEvent[/COLOR].CLICK,[COLOR=#2B91AF]StartGame[/COLOR]);
}
[COLOR=#00008B]private[/COLOR] [COLOR=#00008B]function[/COLOR] [COLOR=#2B91AF]StartGame[/COLOR](e:[COLOR=#2B91AF]Event[/COLOR])
{
    stage.removeChild(BG);
    stage.removeChild(start_btn);
    createBubble();

}

[COLOR=#00008B]private[/COLOR] [COLOR=#00008B]function[/COLOR] createBubble()
{
    [COLOR=#00008B]var[/COLOR] [COLOR=#2B91AF]Bubble[/COLOR]:bubble= [COLOR=#00008B]new[/COLOR] bubble();
    [COLOR=#2B91AF]Bubble[/COLOR].y=[COLOR=#800000]200[/COLOR];
    [COLOR=#2B91AF]Bubble[/COLOR].x= randomRange([COLOR=#800000]50[/COLOR],[COLOR=#800000]1100[/COLOR]);
    [COLOR=#2B91AF]Bubble[/COLOR].alpha= .[COLOR=#800000]5[/COLOR];
    addChild([COLOR=#2B91AF]Bubble[/COLOR]);
}


[COLOR=#00008B]private[/COLOR] [COLOR=#00008B]function[/COLOR] randomRange(min:[COLOR=#2B91AF]Number[/COLOR],[COLOR=#2B91AF]Max[/COLOR]:[COLOR=#2B91AF]Number[/COLOR]):[COLOR=#2B91AF]Number[/COLOR]
{
    [COLOR=#00008B]return[/COLOR] min + ([COLOR=#2B91AF]Math[/COLOR].random() * ([COLOR=#2B91AF]Max[/COLOR] - min));
}

[COLOR=#00008B]private[/COLOR] [COLOR=#00008B]function[/COLOR] init() 
{
    [COLOR=#00008B]for[/COLOR] ([COLOR=#00008B]var[/COLOR] count:[COLOR=#2B91AF]Number[/COLOR] = [COLOR=#800000]0[/COLOR]; count<bubbleMax; count++)
    {
        createBubble();
    }
}
init();

}

}
[FONT=Arial][COLOR=#000000]bg, start_button, and bubble are all movie clips made in flash (and been given a as3 class) I expect 50 bubbles, But[/COLOR][COLOR=#000000] can only see one… thanks for help![/COLOR][/FONT]