coliders are not working

hey, so i`m making a game and the bullets that hit the player are damadging him but the ones that hit the ennemy are not, the player is a capsule all made in Unity but the gun, the turret was fully made in cheeta 3D so I added a box colider to it and tried just adding coliders in the prefab options annyway I cant find a reason for this to hapen other than a bug. so here are the codes I used.

// under update in the shooting code
if(Input.GetButtonDown("Fire1")&& fire)
    {
    	if (auto){}
    	
    	else
    	{
    	clone = Instantiate(projectile, transform.position, transform.rotation);
        clone.velocity = transform.TransformDirection( Vector3 (0, 0, speed));
		AudioSource.PlayClipAtPoint(sound, transform.position, 1);
		bulletAmount -= 1;
    	}
    }	

// under the health script and update
var dead = false;
var health = 100;
var damage = 10;
var player = true;
var ennemy = false;
var PlayerHealthDisplay: GUIText;

function DisplayAmount () {
    PlayerHealthDisplay.text = "" + health;
}

function Start () {

}



function OnControllerColliderHit(hit : ControllerColliderHit) 
{    
	
	if (hit.gameObject.tag == "fallout")
	{
		dead = true;
	}
	
	if (hit.gameObject.tag == "bullet")
	{
	 if (player)
	 {
	 health -= damage;
	 }
	 if (ennemy)
	 {
	 health  -= damage;
	 }
	}
	
	if (health < 1)
	{
	dead = true;
	}
	
}

function Update()
{
		if (dead && player)
       {
           Debug.Log("Died, Respawning!");
           health = 100;
           transform.position = Vector3(-9,2,-48);
           dead = false;
       }
       if (dead && ennemy)
       {
       		Destroy(gameObject);
       }
       
}

// and under the bullet code
var lifeTime = 100;


function Awake()
{
	Destroy (gameObject, lifeTime*Time.deltaTime);
}
function OnCollisionEnter(collision : Collision)
{
	Destroy (gameObject,0.1);
}

sorry for the ton of code and thank you all

Hey, try to add Rigidbodys with collisiondetection to your enemys this should work :).