collision with enemy that give damage

im creating a fps but the thing is that when my bullet hit him it does not give damage so that kind of a probleme i aready got a damage recever from the fps tut but i dont know how to make my bullet do damage when he collide with the enemy. can you help me with that

here is the damage receiver script :

var hitPoints = 100.0;
var detonationDelay = 0.0;
var explosion : Transform;
var deadReplacement : Rigidbody;

function ApplyDamage (damage : float) {
    // We already have less than 0 hitpoints, maybe we got killed already?
    if (hitPoints <= 0.0)
        return;

    hitPoints -= damage;
    if (hitPoints <= 0.0) {
        // Start emitting particles
        var emitter : ParticleEmitter = GetComponentInChildren(ParticleEmitter);
        if (emitter)
            emitter.emit = true;

        Invoke("DelayedDetonate", detonationDelay);
    }
}

function DelayedDetonate () {
    BroadcastMessage ("Detonate");
}

function Detonate () {
    // Destroy ourselves
    Destroy(gameObject);

    // Create the explosion
    if (explosion)
        Instantiate (explosion, transform.position, transform.rotation);

    // If we have a dead barrel then replace ourselves with it!
    if (deadReplacement) {
        var dead : Rigidbody = Instantiate(deadReplacement, transform.position, transform.rotation);

        // For better effect we assign the same velocity to the exploded barrel
        dead.rigidbody.velocity = rigidbody.velocity;
        dead.angularVelocity = rigidbody.angularVelocity;
    }

    // If there is a particle emitter stop emitting and detach so it doesnt get destroyed
    // right away
    var emitter : ParticleEmitter = GetComponentInChildren(ParticleEmitter);
    if (emitter) {
        emitter.emit = false;
        emitter.transform.parent = null;
    }
}

// We require the barrel to be a rigidbody, so that it can do nice physics
@script RequireComponent (Rigidbody)

I hope that you can help me

I didn't see a way that you deduct damage from the enemy when it gets hit by the bullet. Either you need to make `var hitPoints` a static(global) variable with which the instantiated bullet script can deduct from upon collision. else you could put an if statement for the collision detection stating something like `if (collision == findwithtag ("bullet"))` hitPoints = hitPoints - bulletDamage (of course add a bulletDamage variable at the top)

I might get it wrong, but all that script could be replaced by something like:

var hitPoint:float = 100;

function OnCollisionEnter(coll:Collision){
    if(coll.gameObject.tag=="bullet"){ hitPoint -= bulletDamage }
}

bulletDamage could be on an inert script on the bullet itself in case you have different bullets. Or the other way around, with the bullet looking for the player then decreasing a static variable. Or even the bullet calling a public function on the player, taking different parameters:

public function TakeDamage(damage:float,pushBack:float,specificAreaHit:Transform){
    //look for headshot, take damage, push character back
}