Error : Type Coercion failed:

1

I am getting this error

TypeError: Error #1034: Type Coercion failed: cannot convert flash.events::TimerEvent@2c7eba1 to flash.utils.Timer.
at flash.utils::Timer/flash.utils:Timer::_timerDispatch()
at flash.utils::Timer/flash.utils:Timer::tick()

Enemy.as contains

package 
{
    import flash.display.MovieClip;
    public class Enemy extends MovieClip 
    {
        public function Enemy() 
        {
            x = 100;
            y = -20;
            trace('Enemy is coming...');
        }
        
        public function moveDownaBit():void 
        {
            y = y+3;
        }

    }
}

Game.as

package 
{
    import flash.display.MovieClip;
    import flash.utils.Timer;
    import flash.events.TimerEvent;
    
    public class Game extends MovieClip
    {
        public var enemy:Enemy;
        public var gameTimer:Timer;
        
        public function Game() 
        {
            enemy = new Enemy();
            addChild(enemy);
            
            gameTimer = new Timer(25);
            gameTimer.addEventListener(TimerEvent.TIMER, moveEnemy);
            gameTimer.start();
        }
        
        public function moveEnemy (timerEvent:Timer):void 
        {
            enemy.moveDownaBit();
        }
    
    }    
}

What am I missing ?