2D dice rolling

You have a lot of variables that are never being set but you are using them. I have made some small mods to your code that hopefully will put you on track

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
  
 public class DiceRoll : MonoBehaviour
 {
     public Sprite[] Dice;
 
     public Text rollText;
     public int rolls;
     public int rollValue;
     public Text totalText;
     public int total;
     public int[] totalValue;
 
     private bool isRolling;
     private float totalTime;
     private float intervalTime;
     private int currrentDie;
     private bool dieRolled;
     private int currentTotal;
 
     Image die;
 
     void Start()
     {
         rolls = 0;
         total = 0;
 
         // moved this here because there is no need  to continually get the same object
         die = GameObject.Find("DieImage").GetComponent<Image>();
         UpdateRolls();
         Init();
     }
 
     private void Init()
     {
         totalTime = 0.0f;
         intervalTime = 0.0f;
         currrentDie = 0;
         dieRolled = false;
         die.sprite = Dice[currrentDie];
     }
 
     void Update()
     {
         if (isRolling)   
         {
             intervalTime += Time.deltaTime;
             totalTime += Time.deltaTime;
 
             if (intervalTime >= 0.1f)
             {
                 //change die & rotation
                 currrentDie = Random.Range(0, 6);
                 die.transform.Rotate(0, 0, Random.Range(0, 360));
 
                 //set image to selected die
                 die.sprite = Dice[currrentDie];
                 intervalTime -= 0.1f;
             }
 
             if (totalTime >= 2.00f)
             {
                 isRolling = false;
                 dieRolled = true;
                 AddRolls(rollValue);
                 // removed the parameter because AddTotal() is called from wone place with same parameter
                 AddTotal();
             }
         }
     }
 
     public void DieImage_Click()
     {
         if (!dieRolled)
         {
             isRolling = true;  
         }
 
         if (!isRolling)
         {
             Init();   
             isRolling = true;
         }
     }
 
     public void PanelTestButton_Click()
     {
         GameObject panel = GameObject.Find("DiePanel");
         Animator animator = panel.GetComponent<Animator>();
         animator.Play("DiePanelOpen");
     }
 
     public void PanelOKButton_Click()
     {
         GameObject panel = GameObject.Find("DiePanel");
         Animator animator = panel.GetComponent<Animator>();
         animator.Play("DiePanelClose");
         rolls = 0;
         total = 0;
         UpdateRolls();
     }
 
     public void AddRolls(int newRollValue)
     {
         rolls += newRollValue;  
         UpdateRolls();
     }
 
     // removed the parameter because AddTotal() is called from wone place with same parameter
     public void AddTotal()
     {
         // value is the true amount of the die face (currrentDie is 0 base so add 1)
         int value = currrentDie + 1;
         totalValue[currrentDie] += value; // add value to totalValue of current die
         total += value;                   // add value to total
         UpdateRolls();
     }
 
     void UpdateRolls()
     {
         rollText.text = "Rolls: " + rolls;
         totalText.text = "Total: " + rolls;
     }
 }