My rockets don't do damage?

When I shoot my rockets at an Ai the dont do any damage, how do I change that? I used the standard script from the FPS Turtorial, I had to make a madofication to it so that my rocket would shoot farther, I deleted the second part of the script,that started with FunctionUpdate. Did I delete the part needed to deal damage? This is what my script looks like:

// The reference to the explosion prefab var explosion : GameObject; var timeOut = 8.0;

function OnCollisionEnter (collision : Collision) { // Instantiate explosion at the impact point and rotate the explosion // so that the y-axis faces along the surface normal var contact : ContactPoint = collision.contacts[0]; var rotation = Quaternion.FromToRotation(Vector3.up, contact.normal); Instantiate (explosion, contact.point, rotation);

// And kill our selves
Kill ();    


function Kill () { // Stop emitting particles in any children var emitter : ParticleEmitter= GetComponentInChildren(ParticleEmitter); if (emitter) emitter.emit = false;

// Detach children - We do this to detach the trail rendererer which should be set up to auto destruct

// Destroy the projectile


@script RequireComponent (Rigidbody)

you have to add this script on the prefab "explosion" your instantiating in this line of yours

 Instantiate (explosion, contact.point, rotation);

then you just have to tweak some parts like add the ability of your AI to receive damage, the proper Collider tags so when the explosion happens, it knows who receives damage.