Script Problem Shooting

I need help with this Script.

var thePrefab : GameObject;
    var power : float = 5000.0;

    function Update () 
    {
        if (Input.GetButtonDown ("Fire1"));
        (Instantiate (GameObject, transform.position, transform.rotation));
        rigidbody.AddForce(Vector3(0,0,power));
    }

It says something like this...

Assets/Standard Assets/Scripts/ShootBomb.js(7,22): BCE0023: No appropriate version of 'UnityEngine.Object.Instantiate' for the argument list '(System.Type, UnityEngine.Vector3, UnityEngine.Quaternion)' was found.

var thePrefab : GameObject;
var power : float = 5000.0;
function Update () 
{
    if (Input.GetButtonDown ("Fire1"))
    {
    Instantiate (GameObject, transform.position, transform.rotation); 
    }

    rigidbody.AddForce(Vector3(0,0,power));
}

Put that on a game object... The script wasn't right. Might work now.

you could try this:

var Bullet : Transform;    

function Update ()
    {
        if(Input.GetButtonDown("Fire1"))
        {
             Instantiate(Bullet,transform.position,transform.rotation);

             Bullet.rigidbody.AddForce(transform.forward * 5000);
        }
    }

This should help :)