Problem with disabling mouselook script

Questions & Answers
1

I want to make a script that disables the character controller’s mouselook script when the player enters a trigger, but when I enter the trigger it gives this error:

Object reference not set to an instance of an object.

This is my script: (the script I want to disable is called controlgui)

private var inRange: boolean = false;
private var recttext = Rect((Screen.width-w)/2, (Screen.height-100), w, h);
var customGUI : GUIStyle;
var text1 : String;
var controller : GameObject;
var w = 250;
var h = 300;

function OnTriggerEnter(other:Collider) {
	if (other.tag == "Player") {
		inRange =  true;
	}
}

function OnTriggerExit(other:Collider) {
	if (other.tag == "Player") {
		inRange =  false;
	}
}

function OnGUI() {
	if(inRange) {
		GUI.Label(recttext,text1,customGUI);
	}
}

function Update () {
	if (inRange){
	controller.GetComponent(controlgui).enabled = false;
	}	
}
2

Here’s what I do:

var MouseLookScript : MouseLook;

function OnTriggerEnter (col : Collider) {
if(col.gameObject.tag == "Player") {
Entered = true;

}
}
function OnGUI(){
if(Entered){
MouseLookScript.enabled = false;
}
}
function OnTriggerExit (col : Collider) {
if(col.gameObject.tag == "Player") {
Entered = false;
MouseLookScript.enabled = true; 
}
}