Hiding a preview once video starts playing

Question

I am trying to hide a preview that I inserted with some AS3. The preview works and I use this code to create it.
var preview:Loader = new Loader ();
loadPreview (preview, "gotgame.png");
addChild(movie_flv);
function loadPreview (loader:Loader, previewFile:String) :void {
var u:URLRequest = new URLRequest (previewFile);
loader.load(u);
movie_flv.addChild(loader);
Now I am trying to hide the preview once the video starts playing. I tried the code below that I got from a tutorial but its not working and giving me this error "1046: Type was not found or was not a compile-time constant: VideoEvent." Does anyone see the flaw in my code?
movie_flv.addEventListener(VideoEvent.PLAYING_STAT E_ENTERED, onPlay);
function onPlay(evt:VideoEvent):void {
preview.visible=false;

Answer 1

use:
import flash.video.VideoEvent;