Hi there first of all i want to say i have been following BergZerg arcade tutorial on rpg game. But on tutorial 08-10 i ran into a problem as stated as the title. Here is the image on what the problem is 
and here is the code
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class targeting : MonoBehaviour {
public List targets;
private Transform selectedTarget;
private Transform myTransform;
// Use this for initialization
void Start () {
targets = new List<Transform>();
selectedTarget = null;
myTransform = transform;
AddAllEnemies();
}
public void AddAllEnemies()
{
GameObject[] go = GameObject.FindGameObjectsWithTag("enemy");
foreach(GameObject enemy in go)
AddTarget(enemy.transform);
}
private void SortTargetsByDistance()
{
targets.Sort(delegate(Transform t1, Transform t2)
{ return Vector3.Distance(t1.position, myTransform.position).CompareTo(Vector3.Distance(t2.position, myTransform.position)); });
}
public void AddTarget(Transform enemy)
{
targets.Add(enemy);
}
private void TargetEnemy()
{
if(selectedTarget == null)
{
SortTargetsByDistance();
selectedTarget = targets[0];
}
else
{
int index = targets.IndexOf(selectedTarget);
if(index < targets.Count - 1)
{
index++;
}
else
{
index = 0;
}
DeselectTarget();
selectedTarget = targets[index];
}
SelectedTarget();
}
private void SelectTarget()
{
SelectedTarget.renderer.Marterial.color = Color.red;
playerattack pa = (playerattack)GetComponent("playerattack");
pa.target = selectedTarget.gameObject;
}
private void DeselectTarget()
{
selectedTarget.renderer.Marterial.color = Color.blue;
selectedTarget = null;
}
// Update is called once per frame
void Update () {
if(Input.GetKeyDown(KeyCode.Tab))
{
TargetEnemy();
}
}
}