Flash animation working in program preview, not in browser with up to date Flash Player.

Question

After hitting next on this animation you can see there appears to be blank areas on the animation. If you mouse over them you will see buttons appear which is their "over state." When I publish the animation and preview it in Adobe Flash CS5.5 all the buttons are visible and work correctly. It is only in the brower (chrome, firefox, safari) with up to date Flash Player that is is not working. This is happening in a number of animations I created originally in CS4 last year, and am updating them as CS5.5 using AS3.
My application is up to date.

Answer 1

Are you loading those images externally?
Can you share an example of you loading an external file if so? It should look similar to this:
import flash.display.Loader;
import flash.display.Sprite;
import flash.events.Event;
import flash.events.IOErrorEvent;
var myLoader:Loader = new Loader();
myLoader.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR, onErrorHandler);
myLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, onCompleteHandler);
function onErrorHandler(e:IOErrorEvent):void
     // put some visual code here to tell yourself you have a load error
     // otherwise you'll never know
     trace(e);
function onCompleteHandler(e:Event):void
     // add to display list if you wish (a Loader is a displayobject), or add it to a sprite and name it, etc
     addChild(e.target);
If you're not checking for errors then you won't know it's not loading things properly. That is of course if you're loading external assets.