error CS1061 anybody might help me?

hey guys ! In my game (fps) I got that error: "Assets/Scripts/MenuManager.cs(54,53): error CS1061: Type MultiplayerManager' does not contain a definition for StartServer' and no extension method StartServer' of type MultiplayerManager' could be found (are you missing a using directive or an assembly reference?)"

here is my codes:

 using UnityEngine;
 using System.Collections;
 
 public class MenuManager : MonoBehaviour 
 {
     public string CurrentMenu;
 
     public string MatchName = "";
     public string MatchPassword = "";
     public int MatchMaxPlayers = 32;
 
     void Start()
     {
         CurrentMenu = "Main";
     }
 
     void OnGUI()
     {
         if (CurrentMenu == "Main")
             Menu_Main();
         if (CurrentMenu == "Lobby")
             Menu_Lobby();
         if (CurrentMenu == "Host")
             Menu_HostGame();
 
     }
 
     public void NavigateTo(string nextmenu)
     {
         CurrentMenu = nextmenu;
     }
 
     private void Menu_Main()
     {
         if (GUI.Button(new Rect(10, 10, 200, 50), "Host Game"))
         {
             NavigateTo ("Host");
         }
 
         GUI.Label(new Rect(220, 10, 130, 30), "Player Name");
         MultiplayerManager.instance.PlayerName = GUI.TextField(new Rect(400, 10, 200, 30), MultiplayerManager.instance.PlayerName);
     }
 
     private void Menu_HostGame()
     {
         //Buttons Host Game
         if (GUI.Button(new Rect(10, 10, 200, 50), "Back"))
         {
             NavigateTo ("Main");
         }
 
         if(GUI.Button(new Rect(10,60,200,50), "Start Server"))
         {
             MultiplayerManager.instance.StartServer (MatchName, MatchPassword, MatchMaxUsers);
         }
 
         GUI.Label(new Rect(220, 10, 130, 30), "Match Name");
         MatchName = GUI.TextField (new Rect(400, 10, 200, 30), MatchName);
 
         GUI.Label(new Rect(220, 50, 130, 30), "Match Password");
         MatchPassword = GUI.PasswordField (new Rect(400, 50, 200, 30), MatchPassword, '*');
 
         GUI.Label(new Rect(220, 90, 130, 30), "Match Max Players");
         GUI.Label(new Rect(400, 90, 200, 30), MatchMaxPlayers.ToString());
         MatchMaxPlayers = Mathf.Clamp (MatchMaxPlayers, 8, 32);
 
         if (GUI.Button(new Rect(425, 90, 25, 30), "+"))
             MatchMaxPlayers += 2;
         if (GUI.Button(new Rect(450, 90, 25, 30), "-"))
             MatchMaxPlayers -= 2;
     }
 
     private void Menu_Lobby()
     {
     
     }
 
 }
 

and

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class MultiplayerManager : MonoBehaviour 
 {
     public static MultiplayerManager instance;
 
     public string PlayerName;
 
     private string MatchName = "";
     private string MatchPassword = "";
     private int MatchMaxUsers = 32;
 
     public List<MPPlayer> PlayerList = new List<MPPlayer>();
 
     void Start()
     {
         instance = this;
     }
 
     public void StarServer(string servername, string serverpassword, int maxusers)
     {
         MatchName = servername;
         MatchPassword = serverpassword;
         MatchMaxUsers = maxusers;
         Network.InitializeServer(MatchMaxUsers, 2550, false);
         Network.InitializeSecurity();
 
     }
 
     void OnServerInitialized()
     {
         Server_PlayerJoinRequest("", Network.player);
     }
 
     void OnConnectedToServer()
     {
         networkView.RPC ("Server_PlayerJoinRequest", RPCMode.Server, "", Network.player);
     }
 
     void OnPlayerDisconnected(NetworkPlayer id)
     {
         networkView.RPC ("Client_RemovePlayer", RPCMode.All, id);
     }
 
     [RPC]
     void Server_PlayerJoinRequest(string playername, NetworkPlayer view)
     {
         networkView.RPC ("Client_AddPlayerToList", RPCMode.All, playername, view);
     }
 
     [RPC]
     void Client_AddPlayerToList(string playername, NetworkPlayer view)
     {
         MPPlayer tempplayer = new MPPlayer();
         tempplayer.PlayerName = playername;
         tempplayer.PlayerNetwork = view;
         PlayerList.Add(tempplayer);
     }
 
     [RPC]
     void Client_RemovePlayer(NetworkPlayer view)
     {
         MPPlayer temppl = null;
         foreach(MPPlayer pl in PlayerList)
         {
             if(pl.PlayerNetwork == view)
             {
                 temppl = pl;
             }
         }
         if (temppl != null)
         {
             PlayerList.Remove (temppl);
         }
     }
 }
 
 public class MPPlayer
 {
     public string PlayerName = "";
     public NetworkPlayer PlayerNetwork;
 }

Thanks for helping me.