Linha do tempo histórica

Eu precisava fazer uma rolagem horizontal, porque não cabe tudo na stage os anos, alguém conhece um tutorial?

Eu tentei improvisar com o que eu sabia mas o código de navegação da linha do tempo ficou extenso confuso e aparece o erro:

TypeError: Error #1009: Não é possível acessar uma propriedade ou um método de uma referência de objeto nula.

at linha_malvinas2_fla::datas_mc_1/frame1()

código:

stop();

import fl.transitions.Tween;
import fl.transitions.easing.*;
import fl.transitions.TweenEvent;

var tween:Tween;

ano1982_btn.addEventListener(MouseEvent.CLICK, ano1982, false, 0, true);
mar19_btn.addEventListener(MouseEvent.CLICK, mar19, false, 0, true);
mar26_btn.addEventListener(MouseEvent.CLICK, mar26, false, 0, true);
abr2_btn.addEventListener(MouseEvent.CLICK, abr2, false, 0, true);
abr5_btn.addEventListener(MouseEvent.CLICK, abr5, false, 0, true);
abr12_btn.addEventListener(MouseEvent.CLICK, abr12, false, 0, true);
abr17_btn.addEventListener(MouseEvent.CLICK, abr17, false, 0, true);
abr25_btn.addEventListener(MouseEvent.CLICK, abr25, false, 0, true);
mai1_btn.addEventListener(MouseEvent.CLICK, mai1, false, 0, true);
mai4_btn.addEventListener(MouseEvent.CLICK, mai4, false, 0, true);
mai7_btn.addEventListener(MouseEvent.CLICK, mai7, false, 0, true);
mai11_btn.addEventListener(MouseEvent.CLICK, mai11, false, 0, true);
mai18_btn.addEventListener(MouseEvent.CLICK, mai18, false, 0, true);
mai21_btn.addEventListener(MouseEvent.CLICK, mai21, false, 0, true);
mai28_btn.addEventListener(MouseEvent.CLICK, mai28, false, 0, true);
jun4_btn.addEventListener(MouseEvent.CLICK, jun4, false, 0, true);
jun14_btn.addEventListener(MouseEvent.CLICK, jun14, false, 0, true);

function ano1982(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(2);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);
}

function mar19(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(3);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);
}

function mar26(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(4);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);
}

function abr2(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(5);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 700, 40, 1, true);
}

function abr5(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(6);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function abr12(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(7);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function abr17(e:MouseEvent):void {

MovieClip(root).linha1_mc.gotoAndStop(8);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function abr25(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(9);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function mai1(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(10);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function mai4(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(11);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function mai7(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(12);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function mai11(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(13);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function mai18(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(14);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function mai21(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(15);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function mai28(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(16);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

function jun4(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(17);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);
}

function jun14(e:MouseEvent):void {

 MovieClip(root).linha1_mc.gotoAndStop(18);

 tween = new Tween(MovieClip(root).linha1_mc, "x", Strong.easeOut, 600, 40, 1, true);

}

av1_btn.addEventListener(MouseEvent.CLICK, avanca1, false, 0, true);

function avanca1(e:MouseEvent):void {

 nextFrame();

}

volta1_btn.addEventListener(MouseEvent.CLICK, volta1, false, 0, true);

function volta1(e:MouseEvent):void {

 prevFrame();

}