null reference exception in transform.position?

Hi there!
I’m ridiculously new to unity and programming as a whole.
I’ve been doing a tutorial that’s worked fantastic right up until this point.

This code is for a ball to drop from the top of the screen, vanish when reaching a certain point at the bottom and then reappears at the top in a different location.

When played the ball just falls continually down and never stops, the consol states: “NullReferenceException: Object reference not set to an instance of an object”

var enemySpeed: int; 
    
function Update (){

amtToMove = enemySpeed * Time.deltaTime;

transform.Translate(Vector3.down * amtToMove); 

if(transform.postition.y <= -5){
	
	transform.position.y = 6;
	
	transform.position.x = Random.Range(-6,6);
	
	
	
}

}

if(transform.postition.y <= -5) ,position spelling wrong.Variable amtToMove not declared.

//Corrected code

var enemySpeed: int; 
private var amtToMove:float;
 
function Update ()
{ 
	amtToMove = enemySpeed * Time.deltaTime;	 
	transform.Translate(Vector3.down * amtToMove); 
 
	if(transform.position.y <= -5)
	{	 
	    transform.position.y = 6;	 
	    transform.position.x = Random.Range(-6,6); 
	 
	}
 
}