ActionScript3.0-キーボードイベントで動くムービークリップ

IME.enabled = false;
stage.addEventListener(KeyboardEvent.KEY_DOWN, moveObj);
function moveObj(e:KeyboardEvent):void{
var d:uint= 10;
var dx:int;
var dy:int;
switch(e.keyCode){
case Keyboard.RIGHT:
dx = d;
break;
case Keyboard.LEFT:
dx=d*-1;
break;
case Keyboard.UP:
dy= d* -1;
break;
case Keyboard.DOWN:
dy=d;
break;
}

mc1.x += dx;
mc1.y += dy;
}