Issue with duplicated button Flash CS4...help!

Question

I am relatively new to Flash...I am trying to figure this out.
I have button1_btn on a frame in the beginning of this animation, and on that frame I script it:
button1_btn.addEventListener(MouseEvent.CLICK, showimage1);
function showimage1(event:MouseEvent):void {
gotoAndPlay("image1");
It works great, but I also have other buttons that eventually take a different frame where that button isn't on.  So I add it to the stage in that frame and assume it will gotoAndPlay("image1") again when clicked, but when I test the movie, and click it on the later frame, nothing happens.
I tried maybe adding the original script to that frame as well, but then I test and it says I have duplicated script and doesn't work.
Why does the original script work for that button, no matter where and when it shows up?  It's the same button essentially, no?
Please help!

Answer 1

Any instance of an item you add has to be in the presence of whatever code is working with it.  So if you add a new instance in a new keyframe, it does not have that original code being assigned to it because that code was assigned just the once back where that code and the original instance is.
One way around this is to use the visible property to hide the button when you don't want it showing, but retain its presence unbroken by keyframes on the timeline.  Another way is to give the button a new nstance name and code where it lies elsewhere on the timeline.