Event Handlers not Working

Question

Hi. I'm trying to get my .fla to go to my 3 movie instances but when the startPage appears, the buttons don't click to the movie instances. I've check the names and these are correct. Can you spot anything in the code? Thanks
package  {
import flash.display.MovieClip;
import flash.events.MouseEvent;
public class Main extends MovieClip
  var startPage:StartPage;
  var hillPage:HillPage;
  var pondPage:PondPage;
  public function Main()
   startPage = new StartPage;
   hillPage = new HillPage;
   pondPage = new PondPage;
   addChild(startPage);
   // Add event listeners
   startPage.hillButton.addEventListener(MouseEvent.CLICK,onHillButtonClick);
   startPage.pondButton.addEventListener(MouseEvent.CLICK,onPondButtonClick);
   hillPage.backToStartButton.addEventListener(MouseEvent.CLICK,onBackButtonClick_Hill);
   pondPage.backToStartButton.addEventListener(MouseEvent.CLICK,onBackButtonClick_Pond);
  //Event handlers
  function onHillButtonClick(event:MouseEvent):void
  addChild(hillPage);
  removeChild(startPage);
function onPondButtonClick(event:MouseEvent):void
  addChild(pondPage);
  removeChild(startPage);
function onBackButtonClick_Hill(event:MouseEvent):void
  addChild(startPage);
  removeChild(hillPage);
  function onBackButtonClick_Pond(event:MouseEvent):void
  addChild(startPage);
  removeChild(pondPage);

Answer 1

are there any error messages?
if not, use the trace function to debug.  eg, place trace functions in your event handlers to see if those functions are being called.