Network Instantiate PlayerPrefab Problem

I have a problem with instantiating my Prefabs on different Clients.

When the first client is connected to server he can move the way he should. But when the second is connected to server there are some problems:

On the first client appears a copy of the first player so I do move 2 Characters (one of them collides with the player of client 2 and the other not. The second player moves the correct way like on the second Client.

Does anyone know how to solve this problem?

Here is my Code:

 using uLink;
 
 using UnityEngine;
 
 public class InstantiateScript : uLink.MonoBehaviour
 {
     public GameObject PlayerPrefab;
     private GameObject playerAvatar;
     public static GUIText lifePointsAvatar;
     public static bool loggedIn;
     private int level;
 
     void OnLevelWasLoaded(int level) 
     {
         if(level==1)
         {    
                 networkView.RPC("Instantiate", uLink.RPCMode.AllBuffered, "test"); 
         }
 
     }
     public void uLink_OnPlayerDisconnected(uLink.NetworkPlayer player)
     {
         // Removing player from network and scene
         uLink.Network.RemoveRPCs(player, 0);
         uLink.Network.DestroyPlayerObjects(player);
     }
 
     [RPC]
     void Instantiate(string test)
     {
             playerAvatar = uLink.Network.Instantiate(PlayerPrefab, transform.position, transform.rotation, 0);
             Debug.Log("Network aware game object is now created on client" + playerAvatar);
             loggedIn = true;
     }
 }