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.

If you want to load the game from the main menu you need to create a gameobject(I recommend an empty) and have the save data stored in a script on the object, also you need to put DontDestroyOnLoad(); in the script so the object can transfer scenes safely. Then when you load the game scene the data will be in a script where you can access it.