Prefab Losing my Variable

I have a script that was written by someone much more experienced than me. It is attached to an enemy. The target variable is the MPC. When I made a prefab of the enemy that is supposed to chase the MPC, the target variable no longer has my MPC attached.

The MPC is named, “poe.” I’d also like the speed constant, not a variable (.1 speed). Any ideas?

 var target : Transform;
 var vel_vec : Vector3;
 var speed : float;
 var distance_poe : float;
function Update()
 vel_vec = target.position - transform.position; // creates the vector from the enemy to you.
 transform.LookAt(target); // enemy looks to you
 transform.Translate(Vector3.forward * speed * Time.deltaTime); // enemy walks to you


in the start method put:

target = GameObject.Find("poe").transform;