Collision will not work

Hey guys I’ve put this collision code onto a bullet prefab in my game however it keeps on giving me the same response.

The error it gives me is
Script error: OnCollisionEnter
This message parameter has to be of type: Collision
The Message will be ignored

In my scene there are objects that can be collided with because they have mesh colliers and I also have a terrain in the scene as well.
here is the code.

var Target : GameObject;
var ObjectName : String = "Bullet";
function OnCollisionEnter(collision : Collision){
if (collision.gameObject.tag == ObjectName){
	("Collision.gameObject.tag equals " +collision.gameObject.tag);
	Debug.Log("target hit");

So yeah someone please help because I’m running out of options that should work but don’t I am also currently using the latest version of unity as well.

Motion of body should be by force or velocity…