Object reference not set to an instance of an object?

I have the error "Object reference not set to an instance of an object". My script:

 function Update () 
 {
     var ray : Ray = Camera.main.ScreenPointToRay (Input.mousePosition);
     var hit : RaycastHit;
     
     if (Physics.Raycast (ray)) 
     {
         **if(hit.collider.gameObject.tag == ("RecomendedMenu"))
         {
             RecomendedMenu.renderer.enabled = true;        
         }
         
         if(hit.collider.gameObject.tag == ("KojiMenu"))
         {
             KojiMenu.renderer.enabled = true;        
         }**
     }
 }

The "tag" parts of my script are the ones that are getting the error. "RecomendedMenu" is the correct tag and the variable "RecomendedMenu" has been declared. What is wrong?