Unity/Photon chat system error.

Hello all, i have recently started to use Unity with photon to produce a simple multi-player game. I have so far got the client connecting perfectly to the cloud service however i cannot seem to get a simple chat system based on rpc calls to function correctly. Upon entering text into the textfield and submition, a null reference error is generated.

Below is a copy of the chat script.

---

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class Chat : Photon.MonoBehaviour
 {
     public static Chat SP;
     public List<string> messages = new List<string>();
 
     private int chatHeight = (int)140;
     private Vector2 scrollPos = Vector2.zero;
     private string chatInput = "";
     private float lastUnfocusTime = 0;
 
     void Awake()
     {
         SP = this;
     }
         
     void OnGUI()
     {        
         GUI.SetNextControlName("");
 
         GUILayout.BeginArea(new Rect(0, Screen.height - chatHeight, Screen.width, chatHeight));
 
         scrollPos = GUILayout.BeginScrollView(scrollPos);
         GUI.color = Color.red;
         for (int i = messages.Count - 1; i >= 0; i--)
         {
             GUILayout.Label(messages[i]);
         }
         GUILayout.EndScrollView();
         GUI.color = Color.white;
 
         GUILayout.BeginHorizontal(); 
         GUI.SetNextControlName("ChatField");
         chatInput = GUILayout.TextField(chatInput, GUILayout.MinWidth(200));
         
         if (Event.current.type == EventType.keyDown && Event.current.character == '\n'){
             if (GUI.GetNameOfFocusedControl() == "ChatField")
             {                
                 SendChat(PhotonTargets.All);
                 lastUnfocusTime = Time.time;
                 GUI.FocusControl("");
                 GUI.UnfocusWindow();
             }
             else
             {
                 if (lastUnfocusTime < Time.time - 0.1f)
                 {
                     GUI.FocusControl("ChatField");
                 }
             }
         }
 
         if (GUILayout.Button("SEND", GUILayout.Height(17)))
             SendChat(PhotonTargets.All);
         GUILayout.FlexibleSpace();
         GUILayout.EndHorizontal();
         GUILayout.EndArea();
     }
 
     public static void AddMessage(string text)
     {
         SP.messages.Add(text);
         if (SP.messages.Count > 15)
             SP.messages.RemoveAt(0);
     }
 
     [RPC]
     void SendChatMessage(string text, PhotonMessageInfo info)
     {
         AddMessage("[" + info.sender + "] " + text);
     }
 
     void SendChat(PhotonTargets target)
     {
         if (chatInput != "")
         {
            photonView.RPC("SendChatMessage", target, chatInput);
            chatInput = "";
         }
     }
 
     void OnLeftRoom()
     {
         this.enabled = false;
     }
 
     void OnJoinedRoom()
     {
         this.enabled = true;
     }
     void OnCreatedRoom()
     {
         this.enabled = true;
     }
 }


 

---

the error generated is:

NullReferenceException: Object reference not set to an instance of an object

Chat.SendChat2 (PhotonTargets target) (at Assets/Networking/Chat.cs:86) Chat.OnGUI () (at Assets/Networking/Chat.cs:58). Any help or advice would be great, as i can't for the life of me fix the issue. This is a slimmer version of the photon chat demo code.