1120: Access of undefined property imageArea

I followed (or so I thought) the tutorial on creating a progressbar for a preloader in Flash CS3. Unfortunately I get the error message: 1120: Access of undefined property imageArea. Wonder what happened since the online tutorial supposedly works. Flash doesn’t like this code:

// Load Image
imageArea.addChild(imageLoader);

The only thing I did differently from the tutorial was load my own exe (and tried with swf) instead of loading the jpg in the online code.

Any clues why I am getting this message, and how to fix?

Thanks for any help.