Event Problems

[Doush.]

I'm currently having a weird problem with a couple events in an app I'm making.

What I'm trying to achieve is when a user double clicks a thumbnail on the stage to trigger the onDoubleClick and when a user clicks once on a thumbnail trigger onClick both of which are inside a screen class which the thumbnails will be inside of.

I only want the single click to trigger if the double click hasn't.

I have it working but I have a little problem in the debug window that I cant see why its happening.

Here is the setup;

The part of the Screen class that creates the thumbnail and adds its listeners

var thumb:Thumbnail = new Thumbnail();
thumb.addEventListener(Thumbnail.THUMB_CLICK, onClick);
thumb.addEventListener(Thumbnail.THUMB_DOUBLE_CLICK, onDoubleClick );

Here is the functions

private function onClick(e:Event) {
trace("clicked");
}

private function onDoubleClick(e:Event) {
trace("double clicked");
} 

Now here is the guts of the Thumbnail class

public class Thumbnail extends MovieClip {

public static const THUMB_DOUBLE_CLICK:String = "double_click";
public static const THUMB_CLICK:String = "click";

var timer:Timer;

public function Thumbnail() {

addEventlistener( MouseEvent.CLICK, onClick);
addEventlistener( MouseEvent.DOUBLE_CLICK, onDoubleClick);

}

private function onClick(e:MouseEvent) {

timer = new Timer(250,1);
timer.addEventListener(TimerEvent.TIMER_COMPLETE, onTimerComplete);
timer.start();

}

private function onDoubleClick(e:MouseEvent) {

if(timer != null) {

timer.stop();
timer.removeEventListener(TimerEvent.TIMER_COMPLETE, onTimerComplete);
timer = null;

dispatchEvent(new Event(THUMB_DOUBLE_CLICK));

}

}

private function onTimerComplete(e:TimerEvent) {

dispatchEvent(new Event(THUMB_CLICK));

}
} 

Now it all works fine but I get a Error:
TypeError: Error #1034: Type Coercion failed: cannot convert flash.events::Event to flash.events.MouseEvent

Now I cannot see anywhere were I'm event trying to cast an event from Event to MouseEvent.

The error says its happening at the onTimerComplete function.

Any thoughts?