Error in log on Tshock Build #501

[Server API] Warning Plugin "DieMob Regions" has had an unhandled exception thrown by one of its GameUpdate handlers:
System.MissingMethodException: Method 'NetMessage.SendData' not found.
  at TerrariaApi.Server.HandlerCollection`1[System.EventArgs].Invoke (System.EventArgs args) [0x00000] in <filename unknown>:0
[Server API] Warning Plugin "Protector" has had an unhandled exception thrown by one of its NetGetData handlers:
System.MissingMethodException: Method 'NetMessage.SendData' not found.
  at TerrariaApi.Server.HandlerCollection`1[TerrariaApi.Server.GetDataEventArgs].Invoke (TerrariaApi.Server.GetDataEventArgs args) [0x00000] in <filename unknown>:0
[Server API] Warning Plugin "DieMob Regions" has had an unhandled exception thrown by one of its GameUpdate handlers:
System.MissingMethodException: Method 'NetMessage.SendData' not found.