Method call not doing anything

Hi guys.

I have to separate classes, on for a header image and the other for a navigation bar. When the user clicks a specific button on the navigation bar, I would like the images in the header to change accordingly. Here is the code:

HeaderClass.as

package com.bethroi
{
	
	import flash.display.*;
	import flash.net.*;
	import flash.events.*;
	import caurina.transitions.*;
	import flash.utils.Timer;
	import com.bethroi.NavClass;
	
	public class HeaderClass extends Sprite
	{
		private var xml:XML;
		private var xmlList:XMLList;
		private var xmlLoader:URLLoader;
		private var imageLoader:Loader;
		public var child1:String;	
		public var child2:String;	
		private var headerImages:HeaderImages;
		private var logoClip:LogoClip;
		private var exLoader:ExLoader;
		public var childRequest:URLRequest;
		public var whichChild:String;
		
		public function HeaderClass()
		{
			xmlLoader = new URLLoader();
			init();
			//trace(child1);
			
			headerImages = new HeaderImages();
			headerImages.x = 0;
			headerImages.y = -500;
			addChild(headerImages);
			Tweener.addTween(headerImages,{x:0, y:-350, time:2});
			
			logoClip = new LogoClip();
			logoClip.alpha = 0;
			logoClip.x = -230;
			headerImages.addChild(logoClip);
			Tweener.addTween(logoClip,{alpha:1, time:2});
			
		}
		
		private function init():void
		{
			xmlLoader.addEventListener(Event.COMPLETE, xmlLoaded);
			
			try
			{
				xmlLoader.load(new URLRequest("data/header.xml"));
			}
			catch(error:Error)
			{
				trace("Error loading XML File");
			}
		}
		
		public function xmlLoaded(event:Event):void
		{			
			xml = XML(event.target.data);
			xmlList = xml.children();
			
			child1 = xmlList[0].attribute("source");
			child2 = xmlList[1].attribute("source");
			
			imageLoader = new Loader();
			loadRequest(child1);
			imageLoader.x = headerImages.x - 372;
			imageLoader.y = -82;
			imageLoader.alpha = 0;
			headerImages.addChild(imageLoader);
			headerImages.setChildIndex(imageLoader,1);
			
			exLoader = new ExLoader();
			headerImages.addChild(exLoader);			
			
			imageLoader.contentLoaderInfo.addEventListener(ProgressEvent.PROGRESS, loadProgress);
			imageLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, loadComplete);
		}
		
		private function loadProgress(event:ProgressEvent):void
		{			
			var percent:Number = Math.round((event.bytesLoaded/event.bytesTotal)*100);
			exLoader.loaderTxt.text = String(percent);
		}
		
		private function loadComplete(event:Event):void
		{
			exLoader.visible = false;
			Tweener.addTween(imageLoader,{alpha:1,time:1});
			//Tweener.addTween(imageLoader,{_brightness:10,time:1});
		}
		
		public function loadRequest(whichChild:String):void
		{
			childRequest = new URLRequest(whichChild);
			imageLoader.load(childRequest);
			//trace(navClass.clickCheck);
			trace(whichChild);
		}
	
	}
}

NavClass.as

package com.bethroi
{
	import flash.display.*;
	import flash.events.*;
	import flash.filters.*;
	import caurina.transitions.*;
	import com.bethroi.HeaderClass;
	
	public class NavClass extends Sprite
	{
		private var navBar:NavBar;
		private var buttonArray:Array = ["HOME", "ABOUT US", "TESTIMONIAL", "GALLERY", "CONTACT US"]; 
		private var urlArray:Array = ["child1", "child2", "TESTIMONIAL", "GALLERY", "CONTACT US"]; 
		private var temp:DisplayObject;
		private var buttonHolder:ButtonHolder;
		private var buttonClip:MovieClip;
		public var clickCheck:String;
		private var headerClass:HeaderClass = new HeaderClass();
		private var ellipseSprite:Sprite;
		private var ellipseGlowFilter:GlowFilter;
		private var ellipseBlurFilter:BlurFilter;
		
		public function NavClass()
		{
			navBar = new NavBar();
			navBar.x = 0;
			navBar.y = 2000;
			addChild(navBar);
			this.setChildIndex(navBar,0);
			Tweener.addTween(navBar,{x:0, y:-238, time:2});
			
			createButtons();
		}
		
		private function createButtons():void
		{
			buttonClip = new MovieClip();
			
			for(var i:uint = 0; i<buttonArray.length; i++)
			{
				buttonHolder = new ButtonHolder();
				navBar.addChild(buttonHolder);
				buttonHolder.x = -135 + ((buttonHolder.width)+12)*i;
				buttonHolder.y = 25;
				buttonHolder.name = "buttonHolder"+(i+1);
				buttonHolder.buttonTxt.text = buttonArray*;
				//trace(buttonHolder.name);
				buttonHolder.buttonMode = true;
				buttonHolder.mouseChildren = false;
				buttonHolder.addEventListener(MouseEvent.CLICK, doClick);
				buttonHolder.addEventListener(MouseEvent.MOUSE_OVER, mouseOver);
				buttonHolder.addEventListener(MouseEvent.MOUSE_OUT, mouseOut);
			}
			
			
		}		
		
		private function doClick(event:MouseEvent):void
		{
			
			if(event.target.name == "buttonHolder1")
			{
				headerClass.loadRequest(headerClass.child1);
				clickCheck = "HOME";
				//trace(clickCheck);
				//trace(urlArray[0]);				
			}
			else if(event.target.name == "buttonHolder2")
			{
				headerClass.loadRequest(headerClass.child2);
				clickCheck = "ABOUT US";
				//trace(urlArray[1]);
			}
		}
       }
}

when a button is clicked* trace(whichChild);* traces the path correctly, but the image does not load in the imageLoader.

Any Help would be appreciated.

Thanks.