Your class CircleExample contain error, you can't call the method addChild because your class need to extend Sprite or MovieClip
To see the current class path of your Fla, just go in File -> Publish settings, near Script : Actionscript 3, click the Actionscript settings icon.
Normally the classpath contain "." for current file directory.
The class file sample.
package {
import flash.display.MovieClip;
public class CircleExample extends MovieClip {
public function CircleExample() {
super();
graphics.beginFill( 0xFF0000 );
graphics.drawCircle( 0, 0, 10 );
}
}
}
In your FLA
var circle:CircleExample = new CircleExample();
circle.x = 20;
circle.y = 30;
addChild( circle );