Checking if a Vector3 is a int

I want to make make my character walk back if he walks into a stone or a tree in a grid based game.

here is my script :

var startPoint : Vector3;
var endPoint : Vector3;
var speed : float;
private var increment : float;
var isMoving : boolean;
var tileSpace : float;
var tileOn : String;
var tile : GameObject [];
var tileStatts; var walkedDir : Vector3;

function Start () {

 startPoint =  transform.position;
 endPoint = transform.position; 

}

function Update () {

 var pos = transform.position;
 
 calculateTileOn ();
 
 
 if(tileOn == "Tree" || tileOn == "Stone"){
     increment = 0;
     isMoving = true;
         switch (walkedDir){
         case Vector3.up :
         startPoint = transform.position;
         endPoint = new Vector3(transform.position.x, transform.position.y - tileSpace, transform.position.z );
         break;
         case Vector3.down :
         startPoint = transform.position;
         endPoint = new Vector3(transform.position.x, transform.position.y + tileSpace, transform.position.z );
         break;
         case Vector3.left :
         startPoint = transform.position;
         endPoint = new Vector3(transform.position.x - tileSpace, transform.position.y, transform.position.z );
         break;
         case Vector3.rigth :
         startPoint = transform.position;
         endPoint = new Vector3(transform.position.x + tileSpace, transform.position.y - tileSpace, transform.position.z );
         break;
         
     }
         
 }
 
 
 
 
 if(increment <=1 && isMoving == true){
     increment += speed/100;
     }
 else{
     isMoving = false;
 
 }
 if(isMoving){
     transform.position = Vector3.Lerp(startPoint, endPoint, increment);
     
 }
 if(Input.GetButton("forward") && isMoving == false){
     increment = 0;
     isMoving = true;
     startPoint = transform.position;
     endPoint = new Vector3(transform.position.x, transform.position.y + tileSpace, transform.position.z );
     walkedDir = Vector3.up;
     
 }    
 
 if(Input.GetButton("backward") && isMoving == false){
     increment = 0;
     isMoving = true;
     startPoint = transform.position;
     endPoint = new Vector3(transform.position.x, transform.position.y - tileSpace, transform.position.z );
     walkedDir = Vector3.down;
 }    
 
 if(Input.GetButton("left") && isMoving == false){
     increment = 0;
     isMoving = true;
     startPoint = transform.position;
     endPoint = new Vector3(transform.position.x - tileSpace, transform.position.y, transform.position.z );
     walkedDir = Vector3.left;
 }    
 
 if(Input.GetButton("rigth") && isMoving == false){
     increment = 0;
     isMoving = true;
     startPoint = transform.position;
     endPoint = new Vector3(transform.position.x + tileSpace, transform.position.y, transform.position.z );
     walkedDir = Vector3.rigth;
 }    
 

}

function calculateTileOn() {

  var hit: RaycastHit2D = Physics2D.Raycast(transform.position, -Vector2.up);
     
     if(1 == 1){
         tileOn = hit.collider.gameObject.tag;
         tile =  GameObject.FindGameObjectsWithTag (tileOn);
         tileStatts = tile.Tile;
         
         
     }
     
     
     
         

}

Could you tell me how to change my script so that the character walks back when it is on a int (center of a Tile).

And could you also tell me what I am doing different with my rigth, because it says Object reference not set to an instance of an object when I press my rigth key.