Actionscript broken?

My Flash is a little strange, I doesn't recognize the UILoader I'm importing, actually when I type import fl.c it doesn't suggest the container library, was this deleted in AS3 or is flash just broken?

package  {

import flash.display.MovieClip;
im开发者_运维百科port fl.containers.UILoader;



public class Tarjetas extends MovieClip {


    public function Tarjetas() {
        var loader:UILoader = new UILoader();
    }
}

}

---

UILoader is a component (like FLVPlayback) which means the component itself needs to be added to your library for the above to work.

This may help:
http://livedocs.adobe.com/flash/9.0/main/flash_as3_components_help.pdf