This is my pause menu script:

var paused : boolean = false; 

var pausedGUI : GUITexture;  

var gameName : String = "Your Game";


var mainMenuSceneName : String;

var pauseMenuFont : Font;
private var pauseEnabled = false;

function Start(){

 pauseEnabled = false;
 Time.timeScale = 1;
 AudioListener.volume = 1;
 Screen.showCursor = false;
}

function Update(){

 //check if pause button (escape key) is pressed
 if(Input.GetKeyDown("escape")){

 //check if game is already paused 
 if(pauseEnabled == true){
 //unpause the game
 pauseEnabled = false;
 Time.timeScale = 1;
 AudioListener.volume = 1;
 Screen.showCursor = false; 
 }

 //else if game isn't paused, then pause it
 else if(pauseEnabled == false){
 pauseEnabled = true;
 AudioListener.volume = 0;
 Time.timeScale = 0;
 Screen.showCursor = true;
 }
 }
}

private var showGraphicsDropDown = false;

function OnGUI() {

 GUI.skin.box.font = pauseMenuFont;
GUI.skin.button.font = pauseMenuFont;

 if(pauseEnabled == true){

 //Make a background box
 GUI.Box(Rect(Screen.width /2 - 100,Screen.height /2 - 150,250,200), "Pause Menu");

 //Make Main Menu button
 if(GUI.Button(Rect(Screen.width /2 - 100,Screen.height /2 - 100,250,50), "Main Menu")){
 Application.LoadLevel(mainMenuSceneName);
 }

 //Make Change Graphics Quality button
 if(GUI.Button(Rect(Screen.width /2 - 100,Screen.height /2 - 50 ,250,50), "Change Graphics Quality")){

 if(showGraphicsDropDown == false){
 showGraphicsDropDown = true;
 }
 else{
 showGraphicsDropDown = false;
 }
 }

 //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 == true){
 if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 - 100 ,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 ,250,50), "Simple")){
 QualitySettings.currentLevel = QualityLevel.Simple;
 }
 if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 50,250,50), "Good")){
 QualitySettings.currentLevel = QualityLevel.Good;
 }
 if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 100,250,50), "Beautiful")){
 QualitySettings.currentLevel = QualityLevel.Beautiful;
 }
 if(GUI.Button(Rect(Screen.width /2 + 150,Screen.height /2 + 150,250,50), "Fantastic")){
 QualitySettings.currentLevel = QualityLevel.Fantastic;
 }

 if(Input.GetKeyDown("escape")){
 showGraphicsDropDown = false;
 }
 }
 }
   if(pauseEnabled == true){ 
 //Save game button
 var box : GUIStyle = "box";   
   if(GUI.Button(Rect(Screen.width /2 - 100,Screen.height /2 ,250,50), "Save Game")){

    GUILayout.BeginVertical(); 
    GUILayout.FlexibleSpace();
    if(GUILayout.Button("Save Game"))
    {
       LevelSerializer.SaveGame(gameName);
    }
    GUILayout.Space(60);
    for(var sg in LevelSerializer.SavedGames[LevelSerializer.PlayerName]) { 
       if(GUILayout.Button(sg.Caption)) { 
         sg.Load(); 
         Time.timeScale = 1;
         } 
    } 
    GUILayout.FlexibleSpace();
    GUILayout.EndVertical();
    GUILayout.EndArea();
    //Make quit game button
 if (GUI.Button (Rect (Screen.width /2 - 100,Screen.height /2 + 50,250,50), "Quit Game")){
 Application.Quit();
 }


}

}

}

My problem is that the quit game button doesn't show, all the other buttons show when I pause the game but the quit game button just isn't there.