Help with accessing MC within a dynamically load MC

Question

I'm developing a website for school and in an effort to make it eaier to update i'm attempting to make it as dynamic as possible.  So far I've been able to load in MC's dynamically.  These MC's banners are made up of smaller MC's themselves.  When the mouse goes over one the banners, I want to access one of it's child MC's.  This is what I have so far:
//the banners to be loaded are set in the library to export with a class matching their respective names
//when page loads...
//Create class names
for(var i:int = 1; i<=1; i++)
    placeBanner("bannerMC" +i);
    var test:String = "bannerMC" +i;
    trace(test);
//import banner from library
function placeBanner(bannerClass:String)
    var tempClass:Class = getDefinitionByName(bannerClass) as Class;
    var newBanner:MovieClip = new tempClass() as MovieClip;
    newBanner.name = "bannerMC"+i;
    newBanner.x = 29;
    newBanner.y = 100 +(129*(i-1));
    addChildAt(newBanner,4);
    trace("placing Entry: " +newBanner.name);
    newBanner.buttonMode = true;
    newBanner.addEventListener(MouseEvent.ROLL_OVER, overBanner);
    newBanner.addEventListener(MouseEvent.ROLL_OUT, outBanner);
    newBanner.addEventListener(MouseEvent.CLICK, clickBanner)
//at this point for ROLL_OVER I want to access a sub movie clip of the bannerMC
//for an alpha tween but it doesn't work!!! I get a "Cannot access a property or method
//of a null object reference," I've been unable to correct this
function overBanner(e:MouseEvent):void
    var cBanner:MovieClip = MovieClip(e.currentTarget);
    trace("Roll_OVER object is: " +cBanner.name);
    var alphaMC:MovieClip = MovieClip(cwork.getChildByName("borderMC"));
    var hiLite:Tween = new Tween(alphaMC, "alpha", Regular.easeIn, .8, 1, .25, true);
    trace("Highlighted child : " +alphaMC.name);
so the above is  overBanner function is my original attempt.  My other attempts also failed aswell.   Any help would be great.  Another question: what would be the easiest way to clear the banner movie clips from the stage when the user is brought to another page of my website?
Thanks
FM2b

Answer 1

Don't assign your bannerMC1 object the name of its class.
I modified your code just to get an example working.  That example has a movieclip in the library with a class name bannerMC1.  bannerMC1 object holds an mc with an instance name borderMC
The code below is what worked to make the border tween in...
import fl.transitions.Tween;
import fl.transitions.easing.*;
import fl.transitions.TweenEvent;
for(var i:int = 1; i<=1; i++)
    placeBanner("bannerMC" +i);
    var test:String = "bannerMC" +i;
    trace(test);
//import banner from library
function placeBanner(bannerClass:String)
    var tempClass:Class = getDefinitionByName(bannerClass) as Class;
    var newBanner:MovieClip = new tempClass() as MovieClip;
    newBanner.name = "bannerM"+i;
    newBanner.x = 29;
    newBanner.y = 100 +(129*(i-1));
    addChild(newBanner);
    trace("placing Entry: " +newBanner.name);
    newBanner.buttonMode = true;
    newBanner.addEventListener(MouseEvent.ROLL_OVER, overBanner);
    //newBanner.addEventListener(MouseEvent.ROLL_OUT, outBanner);
    //newBanner.addEventListener(MouseEvent.CLICK, clickBanner)
//at this point for ROLL_OVER I want to access a sub movie clip of the bannerMC
//for an alpha tween but it doesn't work!!! I get a "Cannot access a property or method
//of a null object reference," I've been unable to correct this
function overBanner(e:MouseEvent):void
    var cBanner:MovieClip = MovieClip(e.currentTarget);
    trace("Roll_OVER object is: " +cBanner.name);
    var alphaMC:MovieClip = MovieClip(cBanner.getChildByName("borderMC"));
    var hiLite:Tween = new Tween(alphaMC, "alpha", Regular.easeIn, 0, 1, 2, true); // I exaggerated the numbers to confirm the tween for myself
    trace("Highlighted child : " +alphaMC.name);