JavaScript OnGUI GuiSkins aren't working, multiple scripts

Hi guys, i’m having a major problem, i just got a GUI Skin made for my game, it looks awesome, i have multiple scripts that i wan’t to apply this skin to. One of them is a Pause menu, another Inventory, and some more. When i try to apply this skin, i get this error:

Assets/Scripts/Inventory.js(44,18): BCE0022: Cannot convert ‘UnityEngine.GUISkin’ to ‘UnityEngine.GUISkin’.

Here’s my Inventory script:

#pragma strict

var InventoryEnabled = false;


var InvWindow : Texture;
var InvClose : Texture;
var Grids : Texture[];
var SideBar : Texture[];
var IlluminatiSkin : GUISkin[];

private var GridValue : float = -1;

function Update(){

	
	if(Input.GetKeyDown("c")){
	
			
		if(InventoryEnabled == true){
			
			InventoryEnabled = false;
			Time.timeScale = 1;
			AudioListener.volume = 1;
			Screen.showCursor = false;	
			GetComponent(MouseLook).enabled = true;
						
		}
		
		
		else if(InventoryEnabled == false){
			InventoryEnabled = true;
			AudioListener.volume = 0;
			Time.timeScale = 0;
			Screen.showCursor = true;
			GetComponent(MouseLook).enabled = false;
			
		}
	}
}

function OnGUI ()
{
	 GUI.skin =  IlluminatiSkin;

	if(InventoryEnabled == true)
	{
		GUI.Box(Rect(Screen.width /2 - 280,Screen.height /2 -280 ,650,500), InvWindow);
		
		//Grid
		GridValue = GUI.SelectionGrid(Rect(Screen.width / 2 - 210, Screen.height / 2 - 200, 500, 200), GridValue, Grids, 4);

		//Side Bars
		
		
	}
	
		
	
}

And here is my script for my pause menu:

var mainMenuSceneName : String;
var pauseMenuFont : Font;
private var pauseEnabled = false;	
var IlluminatiSkin : GUISkin[];		

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

private var showGraphicsDropDown = false;

function OnGUI(){

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

	if(pauseEnabled == true){
		
		//Make a background box
		GUI.Box(Rect(Screen.width /2 - 100,Screen.height /2 - 100,250,200), "Pause Menu");
		
		//Make Main Menu button
		if(GUI.Button(Rect(Screen.width /2 - 100,Screen.height /2 - 50,250,50), "Main Menu")){
			Application.LoadLevel(mainMenuSceneName);
		}
		
		//Make Change Graphics Quality button
			if(GUI.Button(Rect(Screen.width /2 - 100,Screen.height /2 ,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 ,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;
			}
			
			if(Input.GetKeyDown("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();
		}
	}
}

Please could you notify me what is wrong with these, also please could you answer ASAP, many thanks.

If “IlluminatiSkin” is meant to be a reference to a single skin and not a collection, then you should not declare it as an array:

var IlluminatiSkin : GUISkin;

Note also that your pause menu font changes are being applied to whichever skin is in effect before you activate the Illuminati skin.