View ID SceneID: X Level Prefix: Y not found during lookup. Strange behaviour may occur

I get these errors every time I make a new build of my app. When I just open the game for the first time, I don't get errors. But when I make a new build with no new changes, these pop up:

 View ID SceneID: 3 Level Prefix: 0 not found during lookup. Strange behaviour may occur
 Received state update for view id' SceneID: 3 Level Prefix: 0' but the NetworkView doesn't exist
 View ID SceneID: 2 Level Prefix: 0 not found during lookup. Strange behaviour may occur
 Received state update for view id' SceneID: 2 Level Prefix: 0' but the NetworkView doesn't exist

and most importantly:

 Received state update for view ID SceneID: 3 Level Prefix: 0 but no initial state has ever been sent. Ignoring message.

I've tried adding Network.SetLevelPrefix(), I've even got rid of DontDeleteOnLoad Objects. Here's one of my scripts:

 var netView : NetworkView; 
 var mouseCoords : Vector3;
 
 function Awake ()
 {
     
 }
 
 function Update () 
 {
     if(Network.isServer && netView.isMine)
     {
         var mousePos = Input.mousePosition;
         mousePos.x -= Screen.width/2;
         mousePos.y -= Screen.height/2;
         mouseCoords = Vector3(mousePos.x, mousePos.y, 0);
         transform.position = Vector3(mouseCoords.x/37.5, mouseCoords.y/37.5, 10);
     }
 }
 
 function OnSerializeNetworkView(stream : BitStream, info : NetworkMessageInfo) 
 {
     if (stream.isWriting) 
     {
         stream.Serialize(mouseCoords);
     }
     else
     {
         var posReceive : Vector3 = Vector3.zero;
         stream.Serialize(posReceive);
         transform.position = posReceive;
     }    
 }

Please help, I've found nothing that can fix it.