Unable to disable gameObject with children

As the title says, I am unable to disable gameobjects with children. every time I try, I get a "MissingFieldException: UnityEngine.GameObject.enabled" error. I need to disable the game object and not just hide it. The reason is, the gameobject is part of my inventory system, and my character still shoots even if the inventory is open, so to prevent that, I just want to disable this specific object.

I am asking to disable it in the Update Function under "CanAttack".

Here is the script I am using: var CanAttack : GameObject;

 //For handgun scripts ---------------------------------------------------------------------------
 var HandgunAmmo : GUIText;
 var HandgumAmmoCount : ammoCount;
 
 //-------------------------------------------------------------------------------------------------
 
 @script AddComponentMenu ("Inventory/Inventory Display")
 @script RequireComponent(Inventory)
 
 //Store components and adjust the window position.
 function Awake()
 {
 HandgunAmmo.enabled = false;   //hide Handgun ammo count
         
 }
 
 //Update the inv list
 function UpdateInventoryList()
 {
     UpdatedList = associatedInventory.Contents;
     //Debug.Log("Inventory Updated");
 }
 
 function Update()
 {
     
     //Turn the Inventory on and off and handle audio + pausing the game.
     if(Input.GetKeyDown(onOffButton))
     {
     CanAttack.enabled = true;
         if (displayInventory)
         {
             displayInventory = false;
             
             gameObject.SendMessage ("ChangedState", false, SendMessageOptions.DontRequireReceiver);
             gameObject.SendMessage("PauseGame", false, SendMessageOptions.DontRequireReceiver); //StopPauseGame/EnableMouse/ShowMouse
             HandgunAmmo.enabled = false;
             
         }
         else
         {
         CanAttack.enabled = false;
             displayInventory = true;
             
             gameObject.SendMessage ("ChangedState", true, SendMessageOptions.DontRequireReceiver);
             gameObject.SendMessage("PauseGame", true, SendMessageOptions.DontRequireReceiver); //PauseGame/DisableMouse/HideMouse
             HandgunAmmo.enabled = true;
             
         }
     }

When I try it as is, I don't get any errors until I try to open the inventory. I then get an error that says :

 MissingFieldException: UnityEngine.GameObject.enabled
 Boo.Lang.Runtime.DynamicDispatching.PropertyDispatcherFactory.FindExtension (IEnumerable`1 candidates)
 Boo.Lang.Runtime.DynamicDispatching.PropertyDispatcherFactory.Create (SetOrGet gos)
 Boo.Lang.Runtime.DynamicDispatching.PropertyDispatcherFactory.CreateSetter ()
 Boo.Lang.Runtime.RuntimeServices.DoCreatePropSetDispatcher (System.Object target, System.Type type, System.String name, System.Object value)
 Boo.Lang.Runtime.RuntimeServices.CreatePropSetDispatcher (System.Object target, System.String name, System.Object value)
 Boo.Lang.Runtime.RuntimeServices+<SetProperty>c__AnonStorey19.<>m__F ()
 Boo.Lang.Runtime.DynamicDispatching.DispatcherCache.Get (Boo.Lang.Runtime.DynamicDispatching.DispatcherKey key, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
 Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.String cacheKeyName, System.Type[] cacheKeyTypes, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
 Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.Object[] args, System.String cacheKeyName, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
 Boo.Lang.Runtime.RuntimeServices.SetProperty (System.Object target, System.String name, System.Object value)
 InventoryDisplay.Update () (at Assets/Inventory/Scripts/InventoryDisplay.js:93)

Does anyone know how I can fix this?