How do i do this timer?

[Madkiller1]

_root.timer1 = 200;


countdown = function ()
{
	_root.timer1--;
	if (_root.timer1 == 0){
		clearInterval(countdownInterval);
	}
}
stop();

countdownInterval = setInterval(countdown, 250);

I'm on "stage1" and die, then i goto "gameover" stage and press the replay button. (it's a game)
And now this code above is being executed 2 times, it goes twice as fast as i should do. Any help here?

Sorry, I'm new and trying to learn.