Throwing Spheres

I am following a tutorial on throwing crates or something, but I am doing it with fire balls (referred to as 'fire' in script) They appear once i press left click where I am standing, but stay in the air where i was standing and they don't move. Help? Thanks in advance, and Happy Holidays!

JavaScript:

 var Speed = 3.0;
 var firePrefab:Transform;
 
 function Update(){
     if(Input.GetButtonDown("Fire1")){
     var fire = Instantiate(firePrefab, transform.position, Quaternion.identity);
     
     fire.rigidbody.AddForce(transform.foward * 2000);
     }
 }