[Photon-PUN]ObjectPooling Probelm, maybe a different approach ?

Hello there,
I wanna use ObjectPooling for reusing GameObjects.
So i made this ObjectPool Pattern - Pastebin.com.
And Unity give me this Error :

The Problem part is from line 54 to 73.

Its like Instantiate a GameObject with a PhotonView, looking for the GameObject with the viewID but dont find the GameObject, but the viewID is there, ? im confused

changed the Pool script from <pre class="CodeBlock"><code> private Dictionary<Transform, Stack<GameObject>> pools = new Dictionary<Transform, Stack<GameObject>>();</code></pre>
to <pre class="CodeBlock"><code> private Dictionary<int, Stack<GameObject>> pools = new Dictionary<int, Stack<GameObject>>();</code></pre>
no Parenting Objects, just generate unique Pool IDs and everything works fine.