Loosing references when going in playmode

I have a script in a game object that references a script of another game object and a UnityEngine.UI.Text of another one. If I set the references during playmode it works fine. But if I set them in edition mode, then when I hit 'play' the two references are lost (images below).

You can see that GMscript has the two references in the first image and then in the second image (playmode) they have disapeared.

Here you have GMscript :

  #pragma strict  
 
  var PScript : PlayerScript;   
  var txt: UnityEngine.UI.Text;  
  function Start () {  
 
      txt = gameObject.GetComponent.<UnityEngine.UI.Text>(); 
      
      PScript = GetComponent (PlayerScript);
  }
  
  function Update () {  
      txt.text = "Gold:"  + PScript.gold;  
  }