load button in main menu

hello, im trying to make a load game button in my game, but there is allways errors. i can save my game and load my game when im playing but i want to load the game from the main menu to. please help me. This is my script:

 var mainMenuSceneName : String;
 var pauseMenuFont : Font;
 
 private var showGraphicsDropDown = false;
 
 function OnGUI(){
         //Make a background box
         GUI.Box(Rect(Screen.width /2 - 100,Screen.height /2 - 100,250,200), "Darkness");
 
         //Make Main Menu button
         if(GUI.Button(Rect(Screen.width /2 - 100,Screen.height /2 - 50,250,50), "Start"))
             Application.LoadLevel(1);        
 
         //Make Change Graphics Quality button
         if(GUI.Button(Rect(Screen.width /2 - 100,Screen.height /2 ,250,50), "Options"))
         /* EDIT : You can toggle a boolean by affecting its opposite, with ! */
         /*{
             if(showGraphicsDropDown == false)
                 showGraphicsDropDown = true;
             else
                 showGraphicsDropDown = false;
         }*/
         showGraphicsDropDown = !showGraphicsDropDown;
         
 
         //Create the Graphics settings buttons, these won't show automatically, they will be called when
         //the user clicks on the "Change Graphics Quality" Button, and then dissapear when they click
         //on it again....
         if( showGraphicsDropDown ) /* EDIT boolean == true is redundant */
         {
             if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 ,250,50), "Fastest"))
                 QualitySettings.currentLevel = QualityLevel.Fastest;
                 
             if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 50,250,50), "Fast"))
                 QualitySettings.currentLevel = QualityLevel.Fast;
 
             if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 100,250,50), "Simple"))
                 QualitySettings.currentLevel = QualityLevel.Simple;
 
             if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 150,250,50), "Good"))
                 QualitySettings.currentLevel = QualityLevel.Good;
 
             if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 200,250,50), "Beautiful"))
                 QualitySettings.currentLevel = QualityLevel.Beautiful;
 
             if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 250,250,50), "Fantastic"))
                 QualitySettings.currentLevel = QualityLevel.Fantastic;
 
             /* EDIT : Input should not be used in OnGUI */
             //if(Input.GetKeyDown("escape"))
             if( Event.current == EventType.KeyDown )
                 if( Event.current.keyCode == KeyCode.Escape )
                     showGraphicsDropDown = false;
         }        
 
         //Make quit game button
         if (GUI.Button (Rect (Screen.width /2 - 100,Screen.height /2 + 50,250,50), "Quit Game"))
             Application.Quit();
     }

[Edit by Berenger] I deleted empty lines to shorten the code and changed some stuff. Check them out, the have the mention / EDIT ... / before them, with the reason.