Actionscript 3 addChild problems

Question

The error messages from FlashDevelop are rather difficult to translate.

I'm using addChild in several situations, generally with no problems. However, every once in a while I get:

Error: Call to a possibly undefined method addChild.

However, the exact same code works in other classes, and I am importing exactly the same files. Obviously addChild is not an undefined method! Here's the code- works in one module, doesn't work in another.

public var artist:Loader;
public var artistName:Loader;

public function SceneTJ():void {
    artistName = new Loader();
    artistName.load(new URLRequest("images/artistname.jpg"));
    artist = new Loader();
    artist.load(new URLRequest("images/artist.jpg"));
    artistName.x = artistName.y = 0;
    artist.x = 0;
    artist.y = 0;

    addChild(artist);
    addChild(artistName);
}

Answer 1

Got it. Like a dummy, I forgot to add "extends Sprite" after the class declaration.