Why doesn't this script work?? Please help..

I have this script attached to a bullet.
It must destroy itself when it collides with an enemy, but it doesn’t. Why?

var itselfbullet : GameObject;

function OnCollisionEnter (other : Collision){
	if(other.tag == "Enemy")
	{
		Destroy(itselfbullet);
	}
}

function OnCollisionEnter (other : Collision){
if(other.gameObject.tag == “Enemy”)
{
Destroy(gameObject);
}
}