Help with key code!!

Im making a key and door system. So you pick up the key and you use it to unlock a door. So when I test it I can pick up the key. here is the key script, I have assigned to the main camera I also dragged the MainCamera to the object variable:

 var Length : float = 3;
  
 static var HaveKey : boolean = false;
 var ShowText : boolean = false;
  
 var Text : String = "You picked up a key";
  
 var other : GameObject;
  
 function Update () {
  
 var hit : RaycastHit;
        
 var ray : Ray = camera.ViewportPointToRay (Vector3(0.5,0.5,0));
        
 var fwd = transform.TransformDirection (Vector3.forward);
  
 Debug.DrawRay(transform.position, fwd * Length, Color.green);
        
         if(Physics.Raycast(ray, hit, Length))
  
         {      
                
                 hitObject = hit.collider.gameObject;
                
                 if(hitObject.gameObject.tag == "Key")
  
                         {
                
                                 other.GetComponent(Crosshair).TextureChange();
                
                                 if(Input.GetKeyUp(KeyCode.E))
                                 {
                        
                                         GetKey();
                                         Destroy(hitObject);
                                        
                        
                                 }
                                
                                
                         }
                
                         else if(hitObject.gameObject.tag == "Untagged")
                
                         {
                                 other.GetComponent(Crosshair).BackToNormal();
                         }
  
                 }
        
         else if(!Physics.Raycast(transform.position, transform.forward, hit, Length))
         {
                 other.GetComponent(Crosshair).BackToNormal();
         }
        
        
  
 }
  
 function GetKey(){
  
         HaveKey = true;
  
         ShowText = true;
        
         yield WaitForSeconds(3);
        
         ShowText = false;
 }
  
 function OnGUI(){
  
 if(ShowText)
 {
         GUI.Label(Rect(Screen.width /2 -62.5, Screen.height /2 + 50, 200, 100), Text);
 }
  
 }

Also my FirstPersonController is tagged as Player. Please help it's urgent!