nullreference exeptio, object reference not set to an instance of an object

i want to create a simple raycast but i get this error?!
my code:
`var speed : float = 5;
var moveDirection : Vector3 = Vector3.zero;
var senstivity : float = 5;
var mouseX : Vector3;
var grounded : boolean;
var inAir : boolean;

function Update(){
}
function FixedUpdate(){
if(Physics.Raycast(transform.posistion,-transform.up,2.0 )){
}

Move();

Rotate();
}

function Move(){
if(Input.GetAxis(“Horizontal”) || Input.GetAxis(“Vertical”)){
moveDirection = Vector3(-Input.GetAxisRaw(“Horizontal”),moveDirection.y, -Input.GetAxisRaw(“Vertical”));
this.transform.Translate(moveDirection.normalized * speed * Time.deltaTime);
}
}

function Rotate(){
if(Input.GetAxis(“Mouse X”)){
mouseX = Vector3(mouseX.x,Input.GetAxis(“Mouse X”),mouseX.z);
this.transform.Rotate(mouseX.normalized * senstivity * Time.deltaTime);
}
}` please help because i have tried all i know and searched the whole internet

You got just a small typo:
Physics.Raycast(transform.posistion

posistion → position

btw you should use code tag for your code (its that 101010 button)