Unable to move scrollbar

Hi,

I've just added a scroll view to my load level screen. Everything looks right and the bar appears when there's enough files to fill up the window, but I just seem to be unable to click it and move it. The scroll wheel isn't moving it either...

Here's a screenshot of it:

Here's some code:

 function OnGUI () {
 
 if (load == true) {
 
     files = Directory.GetFiles(Application.dataPath + "/Levels/");
     fileCount = Directory.GetFiles(Application.dataPath + "/Levels/").Length;
     GameObject.Find("Main Camera").GetComponent("cameraMove").enabled = false;
 
     GUI.Window(0, Rect((Screen.width / 2) - (windowWidth / 2), (Screen.height / 2) - (windowHeight / 2), windowWidth, windowHeight), LoadButtons, "Select a saved game");
     }
 }

 function LoadButtons (id : int) {    
   
     var scrollVec : Vector2 = new Vector2();
        GUILayout.BeginArea(Rect(4, 20, 185, 150));
        scrollVec = GUILayout.BeginScrollView(scrollVec);
 
     for (var file : String in files)
 
         if (GUILayout.Button(Path.GetFileNameWithoutExtension(file))) {
  
             levelToLoad = Path.GetFileName(file);
             LevelSelected ();
             gridBehaviour.gridClicked = false;
         }
 
     GUILayout.EndScrollView();
     GUILayout.EndArea();
 
         if (GUI.Button (Rect (10,175,170,20),"Cancel")) {
             load = false;
             GameObject.Find("Main Camera").GetComponent("cameraMove").enabled = true;
         }    
     }

This is the last hurdle I face for my little editor, and it's such a silly one... Any help would be greatly appreciated :)