Pause Script Suddenly Stops Working

Hello,

I had a simple pause script (adapted from this tutorial) that I built last night. It worked very well and was 100% reliable. Tonight, it seems to have broken, though I've made no changes to the script (or any other script, for that matter).

The script is here:

 #pragma strict
 
 private var pauseGame : boolean = false;
 private var showGUI : boolean = false;
 
 function Update()
 {
     if(Input.GetButtonDown("Pause"))
     {
         pauseGame = !pauseGame;
 
         if(pauseGame == true)
         {
             Time.timeScale = 0;
             pauseGame = true;
             (GameObject.Find("Main Camera").GetComponent("MouseLook") as MonoBehaviour).enabled = false;
             (GameObject.Find("First Person Controller").GetComponent("MouseLook") as MonoBehaviour).enabled = false;
             showGUI = true;
         }
     }
 
     if(pauseGame == false)
     {
         Time.timeScale = 1;
         pauseGame = false;
         (GameObject.Find("Main Camera").GetComponent("MouseLook") as MonoBehaviour).enabled = true;
         (GameObject.Find("First Person Controller").GetComponent("MouseLook") as MonoBehaviour).enabled = true;
         showGUI = false;
     }
 
     if(showGUI == true)
     {
         (gameObject.Find("PausedText").GetComponent("Text") as MonoBehaviour).enabled = true;
         (gameObject.Find("PausedImage").GetComponent("Image") as MonoBehaviour).enabled = true;
         (gameObject.Find("Crosshair").GetComponent("Image") as MonoBehaviour).enabled = false;
         (GameObject.Find("Main Camera").GetComponent("Blur") as MonoBehaviour).enabled = true;
     }
 
     else
     {
         (gameObject.Find("PausedText").GetComponent("Text") as MonoBehaviour).enabled = false;    
         (gameObject.Find("PausedImage").GetComponent("Image") as MonoBehaviour).enabled = false;
         (gameObject.Find("Crosshair").GetComponent("Image") as MonoBehaviour).enabled = true;
         (GameObject.Find("Main Camera").GetComponent("Blur") as MonoBehaviour).enabled = false;
     }
 }

Now, when I run the game, timeScale goes to 0, but the other functions (disabling MouseLook and toggling the GUI stuff) do not work.

However, if I turn on my PauseGUI by default, it will render (even though it should not per this script) and turn off the first time Escape is tapped, then be unresponsive.

I get this error in the console:

 NullReferenceException: Object reference not set to an instance of an object
 Pause.Update () (at Assets/Scripts/Pause.js:26)
 

The only thing that changed was that I downloaded and imported the Survival Shooter demo, played with it for a few minutes, then deleted it when I discovered how badly it mucked up my folder structure. I did not delete any of the files that this one interacts with (Mouselook and blur are still there) nor did I alter the shape of my prefab.

So... does anyone have any thoughts? Cause I'm at a loss. :D