Flash CS4 compiler Error 1120 when embedding pngs into class instance variables

I have a Flash CS4 (Flash 9 ActionScript 3.0) project that compiles and runs perfectly on my machine. However it is part of a big batch of fla's that I want to compile on another (faster) machine. When I copy the project (the fla and all actionscripts and assets files) to the faster machine, it's Flash CS4 compiler gives me compiler error 1120 "Access of undefined property ButtonPause_PauseNormal".

The property "PauseNormal" is an embedded png. The PNG is available. No transcoder errors. Here's the ActionScript for class "ButtonPause";

package nl.platipus.NissanESM.buttons
{
    import flash.display.*;
    import flash.events.*;

    public class开发者_如何学Python ButtonPause extends Sprite
    {
        [Embed(source="../../../../player/pause.png")]
        private var PauseNormal:Class;

        [Embed(source="../../../../player/pause_mo.png")]
        private var PauseMouseOver:Class;

        private var stateNormal:Bitmap;
        private var stateMouseOver:Bitmap;

        public function ButtonPause()
        {
            stateNormal = new PauseNormal();
            stateNormal.width = 29;
            stateNormal.height = 14;
            stateNormal.alpha = 1;
            addChild(stateNormal);

            stateMouseOver = new PauseMouseOver();
            stateMouseOver.width = 29;
            stateMouseOver.height = 14;
            stateMouseOver.alpha = 0;
            addChild(stateMouseOver);


            width = 29;
            height = 14;

            addEventListener(MouseEvent.MOUSE_OVER, handleMouseOver);
            addEventListener(MouseEvent.MOUSE_OUT,  handleMouseOut );
        }

        private function handleMouseOver(evt:MouseEvent):void
        {
            stateNormal.alpha = 0;
            stateMouseOver.alpha = 1;
        }

        private function handleMouseOut(evt:MouseEvent):void
        {
            stateNormal.alpha = 1;
            stateMouseOver.alpha = 0;
        }
    }
}

(Both machines run the exact same Flash CS4 Profesional Version 10.0.2 installation and both have the exact same publish settings and ActionScript 3.0 settings.)

What's going on?