Gun Switching Error

i am trying to make a shop script for my first person shoot game. i switch weapons buy deleting the old weapon and instantiating a new one from a prefab. the weapon is suppose to auto position it's self according to variables in it's script, those variables are used in the aim script attached to the camera witch is a parent of the gun.

the system works fine except that i get this error when i switch weapons

 transform.localPosition assign attempt for 'vzr8(Clone)' is not valid. Input localPosition is { -45.218674, -0.350000, NaN }.
 UnityEngine.Transform:set_localPosition(Vector3)
 aim:Update() (at Assets/scripts/player/gun/aim.js:33)

can any one tell me what it means and how to fix it. btw here is my shop script

 private var toggle : boolean = false;
 private var player : Transform;
 private var skin: GUIStyle;
 private var bg: Texture;
 
 var guns : Transform[];
 
 function Start(){
     player = gameObject.FindWithTag("Player").transform;
     skin = gameObject.FindWithTag("Master").GetComponent("master_gameInterface").skin;
     bg = gameObject.FindWithTag("Master").GetComponent("master_gameInterface").bg;
 }
 
 function OnGUI() {
     var dist = Vector3.Distance(player.position, transform.position);
 
     myStyle = new GUIStyle();
        myStyle.normal.textColor = Color.cyan;
        myStyle.font = skin.font;
        
     if(dist<5){
         if(Input.GetKey(KeyCode.E)){
             master_gameInterface.pause = true;
             toggle = true;
         }
         if(toggle==false)
             GUI.Label(Rect(Screen.width/2,Screen.height/2,200,200), "Press E to enter Shop", myStyle);
     }
     
     if(master_gameInterface.toggle)
         toggle = false;
     
     if(toggle){
     GUILayout.BeginArea(Rect(Screen.width/2-100,Screen.height/2-200,200,400), bg);
     GUILayout.BeginVertical();
         for(var i=0;i<guns.Length;i++){
             if(GUILayout.Button(guns[i].GetComponent("gun").name, skin)){
                 if(player.GetChild(2).GetChild(0))
                     Destroy(player.GetChild(2).GetChild(0).gameObject);
                 var me = Instantiate(guns[i], player.position, Quaternion.identity);
                 me.parent = player.GetChild(2);
                 me.localPosition = player.GetChild(2).position;
                 player.GetChild(2).GetComponent("aim").gun = me;
             }
         }
         
         GUILayout.Label("\n");
         if(GUILayout.Button("Done", skin)){
             master_gameInterface.pause = false;
             toggle = false;
         }
     GUILayout.EndVertical();
     GUILayout.EndArea();
     }
 }
 
 function deleteGun(){
     for (var child : Transform in transform) {
         child.position += Vector3.up * 10.0;
     }
 }

[Edit by Berenger : code formatting]