Error Code 1120 access of undefined property...help please

Question

I am fairly new to Flash - I have CS4 and am not sure if I am in the right place to get help.
I am trying to build a click through gallery with small buttons that you click on and it switches the larger image out as you click through.
I copied over a gallery I had successfully built with 10 images.  The new gallery has 20 images.
Basically the movie just runs continuously without being able to click on the thumbnails.
I am getting the following compiler errors
Scene1 Layer 'actions', Frame 1, Line 42 1120:Access of undefined property btn11_btn Source - btn11_btn.addEventListener(MouseEvent.CLICK, showimage11);
I get this for image 11 through 20
The following is my code
stop();
btn1_btn.addEventListener(MouseEvent.MOUSE_OVER, showimage1);
function showimage1(event:MouseEvent):void {
gotoAndPlay("label1");
btn2_btn.addEventListener(MouseEvent.CLICK, showimage2);
function showimage2(event:MouseEvent):void {
gotoAndPlay("label2");
btn3_btn.addEventListener(MouseEvent.CLICK, showimage3);
function showimage3(event:MouseEvent):void {
gotoAndPlay("label3");
btn4_btn.addEventListener(MouseEvent.CLICK, showimage4);
function showimage4(event:MouseEvent):void {
gotoAndPlay("label4");
btn5_btn.addEventListener(MouseEvent.CLICK, showimage5);
function showimage5(event:MouseEvent):void {
gotoAndPlay("label5");
btn6_btn.addEventListener(MouseEvent.CLICK, showimage6);
function showimage6(event:MouseEvent):void {
gotoAndPlay("label6");
btn7_btn.addEventListener(MouseEvent.CLICK, showimage7);
function showimage7(event:MouseEvent):void {
gotoAndPlay("label7");
btn8_btn.addEventListener(MouseEvent.CLICK, showimage8);
function showimage8(event:MouseEvent):void {
gotoAndPlay("label8");
btn9_btn.addEventListener(MouseEvent.CLICK, showimage9);
function showimage9(event:MouseEvent):void {
gotoAndPlay("label9");
btn10_btn.addEventListener(MouseEvent.CLICK, showimage10);
function showimage10(event:MouseEvent):void {
gotoAndPlay("label10");
btn11_btn.addEventListener(MouseEvent.CLICK, showimage11);
function showimage11(event:MouseEvent):void {
gotoAndPlay("label11");
btn12_btn.addEventListener(MouseEvent.CLICK, showimage12);
function showimage12(event:MouseEvent):void {
gotoAndPlay("label12");
btn13_btn.addEventListener(MouseEvent.CLICK, showimage13);
function showimage13(event:MouseEvent):void {
gotoAndPlay("label31");
btn14_btn.addEventListener(MouseEvent.CLICK, showimage14);
function showimage14(event:MouseEvent):void {
gotoAndPlay("label14");
btn15_btn.addEventListener(MouseEvent.CLICK, showimage15);
function showimage15(event:MouseEvent):void {
gotoAndPlay("label15");
btn16_btn.addEventListener(MouseEvent.CLICK, showimage16);
function showimage16(event:MouseEvent):void {
gotoAndPlay("label16");
btn17_btn.addEventListener(MouseEvent.CLICK, showimage17);
function showimage17(event:MouseEvent):void {
gotoAndPlay("label17");
btn18_btn.addEventListener(MouseEvent.CLICK, showimage18);
function showimage18(event:MouseEvent):void {
gotoAndPlay("label18");
btn19_btn.addEventListener(MouseEvent.CLICK, showimage19);
function showimage19(event:MouseEvent):void {
gotoAndPlay("label19");
btn20_btn.addEventListener(MouseEvent.CLICK, showimage20);
function showimage20(event:MouseEvent):void {
gotoAndPlay("label20");
Any advice would be great
I dont know if I have to start from scratch - which would be a pain for sure
Thanks

Answer 1

I feel foolish - I solved my own problem!
I figured out that I had not given buttons 11 - 20 an instance name
Once I did that - voila problem solved
Sorry for bothering you all.