Changing the Master Client Issues

Hey,
I am programming on this game right now:
https://www.reddit.com/r/Unity2D/comments/4lxh67/some_gameplay_of_my_hoverball_project_thoughts/

This is how Multiplayer looks at the moment:
https://www.reddit.com/r/Unity2D/comments/4m99xx/photon_networking_object_synchronization/

While trying to implement the multiplayer I have trouble to synchronize the Ball and Boards to let it look smoothly.
I want to change the master client dynamically, but when I call PhotonNetwork.SetMasterClient(...); i get the error message:
"Operation failed: OperationResponse 252: ReturnCode: -2 (CAS update failed: property='248' has value='2'). Parameters: {} Server: GameServer
UnityEngine.Debug:LogError(Object)"

Do you have any idea what is wrong with my code?
Or ideas how to make this kind of game feel good on multiplayer?