Unexpected Error

 private void Main()

This method has one to few closing braces.

Try This..

using UnityEngine; using System.Collections;

public class Menu : MonoBehaviour {

 private string CurMenu;
 public string Name;
 public string MatchName;
 public int Players;
 // Use this for initialization
 void Start () {
     CurMenu = "Main";
     Name = PlayerPrefs.GetString("PlayerName");
 }
 
 // Update is called once per frame
 void Update () {
     
 }
 
 void ToMenu(string menu){
     CurMenu = menu;
 }
 void OnGUI(){
     if (CurMenu == "Main")
         Main();
     if (CurMenu == "Host")
         Host();
     if (CurMenu == "Lobby")
         Host();
 }
 private void Main(){
     //if (GUI.Button(new Rect (0, 0, 128, 32), "Host A Match")) {
     // ToMenu ("Host");
     //}
     if(GUI.Button(new Rect(0,0,128,32),"Host a match")){
         ToMenu("Host");
         Name = GUI.TextField (new Rect (130, 0, 128, 32), Name);
         if (GUI.Button(new Rect (260, 0, 128, 32), "Save")) {
             PlayerPrefs.SetString ("PlayerName", Name);
             
         }
     }
 }
     
     private void Host(){
         if(GUI.Button(new Rect(0,0,128,32),"Start")){
             NetworkManager.Instance.StartServer(MatchName,Players);
             ToMenu("Lobby");
         }
         
         if(GUI.Button(new Rect(0,33,128,32),"Back")){
             ToMenu("Main");
         }
         MatchName = GUI.TextField(new Rect(130,0,128,32),MatchName);
         GUI.Label(new Rect(260,0,128,32),"Match name");
         Players = Mathf.Clamp(Players,0,32);
         GUI.Label(new Rect(260,0,128,32),"Max Players");
         if (GUI.Button (new Rect (222, 33, 32, 32),"+"))
             Players ++;
         GUI.Label (new Rect (192, 33, 64, 32), Players.ToString());
         if (GUI.Button (new Rect (282, 33, 32, 32),"-"))
             Players --;
     }
     
     private void Lobby(){
         if(GUI.Button(new Rect(Screen.width - 128,Screen.height - 64,128,32),"Start")){
             
         }
         
         if(GUI.Button(new Rect(Screen.width - 128,Screen.height - 32,128,32),"Back")){
             ToMenu("Host");
         }
     }
     private void MatchList()
     {
         if (GUI.Button(new Rect(0,33,128,32), "Refresh"))
             {
             MasterServer.PollHostList();
         }
         if (GUI.Button(new Rect(0,33,128,32), "Back"))
             {
             ToMenu ("Main");
         }
         GUILayout.BeginArea(new Rect(Screen.width/ 2, 0, Screen.width / 2, Screen.height), "Server List");
         foreach (HostData hd in MasterServer.PollHostList())
         {
             GUILayout.BeginHorizontal();
             GUILayout.Label(hd.gameName);
             if(GUILayout.Button ("Connect"))
             {
                 Network.Connect(hd);
                 ToMenu("Lobby");
             }
             GUILayout.EndHorizontal();
         }
         GUILayout.EndArea();
     }
 }

The problem was that you were not closing your Main() method so you need to insert a "}" on there, and on lines 76 and 80 you didn't put enough ")" symbols to close the GUI.Button syntax. Here is your code fixed: using UnityEngine; using System.Collections;

 public class Menu : MonoBehaviour {
     
     private string CurMenu;
     public string Name;
     public string MatchName;
     public int Players;
     // Use this for initialization
     void Start () {
         CurMenu = "Main";
         Name = PlayerPrefs.GetString("PlayerName");
     }
     
     // Update is called once per frame
     void Update () {
         
     }
     
     void ToMenu(string menu){
         CurMenu = menu;
     }
     void OnGUI(){
         if (CurMenu == "Main")
             Main();
         if (CurMenu == "Host")
             Host();
         if (CurMenu == "Lobby")
             Host();
     }
     private void Main(){
         //if (GUI.Button(new Rect (0, 0, 128, 32), "Host A Match")) {
         //  ToMenu ("Host");
         //}
         if(GUI.Button(new Rect(0,0,128,32),"Host a match")){
             ToMenu("Host");
             Name = GUI.TextField (new Rect (130, 0, 128, 32), Name);
             if (GUI.Button(new Rect (260, 0, 128, 32), "Save")) {
                 PlayerPrefs.SetString ("PlayerName", Name);    
             }
         }
     }
     private void Host(){
         if(GUI.Button(new Rect(0,0,128,32),"Start")){
             NetworkManager.Instance.StartServer(MatchName,Players);
             ToMenu("Lobby");
         }
 
         if(GUI.Button(new Rect(0,33,128,32),"Back")){
             ToMenu("Main");
         }
         MatchName = GUI.TextField(new Rect(130,0,128,32),MatchName);
         GUI.Label(new Rect(260,0,128,32),"Match name");
         Players = Mathf.Clamp(Players,0,32);
         GUI.Label(new Rect(260,0,128,32),"Max Players");
         if (GUI.Button (new Rect (222, 33, 32, 32),"+")){
             Players ++;
         }
         GUI.Label (new Rect (192, 33, 64, 32), Players.ToString());
         if (GUI.Button (new Rect (282, 33, 32, 32),"-")){
             Players --;
         }
     }
 
     private void Lobby(){
         if(GUI.Button(new Rect(Screen.width - 128,Screen.height - 64,128,32),"Start")){
 
         }
 
         if(GUI.Button(new Rect(Screen.width - 128,Screen.height - 32,128,32),"Back")){
             ToMenu("Host");
         }
     }
     private void MatchList(){
         if (GUI.Button(new Rect(0,33,128,32), "Refresh")){
             MasterServer.PollHostList();
         }
         if (GUI.Button(new Rect(0,33,128,32), "Back")){
             ToMenu ("Main");
         }
         GUILayout.BeginArea(new Rect(Screen.width/ 2, 0, Screen.width / 2, Screen.height), "Server List");
         foreach (HostData hd in MasterServer.PollHostList()){
             GUILayout.BeginHorizontal();
             GUILayout.Label(hd.gameName);
             if(GUILayout.Button ("Connect")){
                 Network.Connect(hd);
                 ToMenu("Lobby");
             }
             GUILayout.EndHorizontal();
         }
         GUILayout.EndArea();
     }
 }

You need a "}" after line 37.