NullReferenceException

I keep getting this error and me and my brother cannot figure out why its saying this. This is the error-

 IndexOutOfRangeException: Array index is out of range.
 (wrapper stelemref) object:stelemref (object,intptr,object)
 BaseCharacter.SetupSkills () (at Assets/Scripts/Character Classes/BaseCharacter.cs:67)
 BaseCharacter.Awake () (at Assets/Scripts/Character Classes/BaseCharacter.cs:26)
 CharacterGenerator.Start () (at Assets/Scripts/Character Classes/CharacterGenerator.cs:11)

This is the Script-

 using System;
 
 public class CharacterGenerator : MonoBehaviour {
     private PlayerCharacter _toon;
 
     //Use this for initialization
     void Start() {
         _toon = new PlayerCharacter ();
         _toon.Awake ();
     }
 
     //Update is called once per frame
     void Update() {
 
     }
 
     void OnGUI() {
         DisplayName (); 
         DisplayAttributes ();
         DisplayVitals ();
         DisplaySkills ();
         }
 
     private void DisplayName() {
         GUI.Label (new Rect (10, 10, 50, 25), "Name:");
         _toon.Name = GUI.TextArea (new Rect (65, 10, 100, 25), _toon.Name);
     }
 
     private void DisplayAttributes() {
     for(int cnt = 0; cnt < Enum.GetValues(typeof(AttributeName)).Length; cnt++) {
         GUI.Label (new Rect(10, 40 + (cnt * 25), 100, 25), ((AttributeName)cnt).ToString () );
         GUI.Label (new Rect(115, 40 + (cnt * 25), 30, 25), _toon.GetPrimaryAttribute(cnt).AdjustedBaseValue.ToString());
         }
     }
 
     private void DisplayVitals() {
         for(int cnt = 0; cnt < Enum.GetValues (typeof(VitalName)).Length; cnt++) {
             GUI.Label (new Rect(10, 40 + ((cnt + 7) * 25), 100, 25), ((VitalName)cnt).ToString ());
             GUI.Label (new Rect(115, 40 + ((cnt + 7) * 25), 30, 25), _toon.GetVital(cnt).AdjustedBaseValue.ToString());
         }
     }
 
     private void DisplaySkills(){
     }
 
 }

It says that its on line 41. Its trying to reference this script-

 public class Vital : ModifiedStat 
 {
     private int _curValue;
 
     public Vital()
     {
         _curValue = 0;
         ExpToLevel = 50;
         LevelModifier = 1.1f;
     }
 
     public int CurValue 
     {
         get
         {
             if(_curValue > AdjustedBaseValue)
                 _curValue = AdjustedBaseValue;
 
             return _curValue;
         }
         set{ _curValue = value;}
     }
 }
     public enum VitalName
     {
         Health,
         Stamina,
         Mana
     }

Thanks!