Multiple instances of an Object-Oriented Scrollbar?

Question

Hi everyone, Ive gone through the Object-Oriented Scrollbar tutorial on gotoandlearn.com. Its working great and I have multiple buttons inside of the moveclip it lives within. The problem occurs when I create another one on the same page. I have put one on frame 1 and the other on frame 5 so that I can select a 'category' and the scrollbar movieclip changes to the relevant buttons.
Ive duplicated the movie clips and changed the instances accordingly. I keep getting these errors in the Output panel when playing my swf;
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at as3_movieplayer_fla::MainTimeline/frame1()
and when I click the like to the second category it comes up with this error;
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at as3_movieplayer_fla::scrollbox_1/thumbUp()
Not really sure what im doing wrong - or even what these mean!
Here is the code from my main actions layer;
stop();
//buttons
btn_advertising.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler);
function mouseDownHandler(event:MouseEvent):void {
    gotoAndStop(1);
btn_corporate.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler2);
function mouseDownHandler2(event:MouseEvent):void {
    gotoAndStop(5);
//video player script
function videoOne(event:MouseEvent):void{
   vidPlayer.source = "flvs/ib_enginuity.flv";
function videoTwo(event:MouseEvent):void{
   vidPlayer.source = "flvs/ib_blists_hill.flv";
function videoOneCorp(event:MouseEvent):void{
   vidPlayer.source = "flvs/ib_explore_enjoy.flv";
function videoTwoCorp(event:MouseEvent):void{
   vidPlayer.source = "flvs/ib_great_year_visit.flv";
//text script
function button1text(event:MouseEvent):void{
   textBox.text = "Ironbridge - Enginuity";
function button2text(event:MouseEvent):void{
   textBox.text = "Ironbridge - Blists Hill";
function button1CORPtext(event:MouseEvent):void{
   textBox.text = "Ironbridge - A Place to Explore and Enjoy";
function button2CORPtext(event:MouseEvent):void{
   textBox.text = "Ironbridge - A Great Year to Visit";
//event listeners
scrollbox.content.button1.addEventListener(MouseEvent.CLICK,videoOne);
scrollbox.content.button1.addEventListener(MouseEvent.CLICK,button1text);
scrollbox.content.button2.addEventListener(MouseEvent.CLICK,videoTwo);
scrollbox.content.button2.addEventListener(MouseEvent.CLICK,button2text);
scrollboxCorp.content.button1Corp.addEventListener(MouseEvent.CLICK,videoOneCorp);
scrollboxCorp.content.button1Corp.addEventListener(MouseEvent.CLICK,button1CORPtext);
scrollboxCorp.content.button2Corp.addEventListener(MouseEvent.CLICK,videoTwoCorp);
scrollboxCorp.content.button2Corp.addEventListener(MouseEvent.CLICK,button2CORPtext);
and also the code from my actions layer inside my movieclip which is on frame 5;
import caurina.transitions.*;
var yOffset:Number;
var yMin:Number = 0;
var yMax:Number = sb.track.height - sb.thumb.height;
sb.thumb.addEventListener(MouseEvent.MOUSE_DOWN, thumbDown);
stage.addEventListener(MouseEvent.MOUSE_UP, thumbUp);
function thumbDown(e:MouseEvent):void
   stage.addEventListener(MouseEvent.MOUSE_MOVE, thumbMove);
   yOffset = mouseY - sb.thumb.y;
function thumbUp(e:MouseEvent):void
   stage.removeEventListener(MouseEvent.MOUSE_MOVE, thumbMove);
function thumbMove(e:MouseEvent):void
   sb.thumb.y = mouseY - yOffset;
   if(sb.thumb.y <= yMin)
      sb.thumb.y = yMin;
   if(sb.thumb.y >= yMax)
      sb.thumb.y = yMax;
   var sp:Number = sb.thumb.y / yMax;
   Tweener.addTween(contentCorp, {y:(-sp*(contentCorp.height-masker.height)),
                        time:1});
   e.updateAfterEvent();
Please help me iron out these problems!!! Many thanks
Dan Williams

Answer 1

hum thats interesting. Could it be my flash player?
Ive 'published' it as an .exe and it works fine.
If i publish to html, the flash player box comes up with that error in it.
If you dismiss all errors then it works fine!?
The error appears in the output part. Its referencing scrollbox_1::frame1:18, but I dont have anything called scrollbox_1?! not sure what is going on.
ignore all that. I just tried exporting it as flash 9 rather than flash 10 and the error has gone!
I suppose thats the answer then!
Thanks for all your help anyway ned, was much appreciated.
Kind Regards
Dan