trouble shooting

ok so i have a simple cube and sphere im trying to make the sphere shoot out of the cube like a gun. the problem is when i shoot the bullets apear but doesnt go anywhere can someone help me

heres the script im using

var Bullet : Transform;
var BulletSpeed : float = 6000;

function Update ()
{
if(Input.GetButtonDown(“Fire1”))
{
Instantiate(Bullet,transform.position,Quaternion.identity);

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

}

When utilizing AddForce, it should be placed in FixedUpdate() and not Update(). When you’re using a new function / method in Unity, you should try and read the documentation carefully because for the most part, Unity did an excellent job in explaining certain aspects of their engine:

“If you want to apply a force over several frames you should apply it inside FixedUpdate instead of Update.”

http://unity3d.com/support/documentation/ScriptReference/Rigidbody.AddForce.html

var Bullet : Transform; var BulletSpeed : float = 6000;

function Update (){ 
    if(Input.GetButtonDown("Fire1"){
        var newBullet = Instantiate(Bullet,transform.position,Quaternion.identity);
        newBullet.rigidbody.AddForce(transform.forward * BulletSpeed);
    }    
}

You forgot to create a instance of the bullet(or something you can refer to).