cannot save button

Failed to call hook 'custombuttons_save' on plugin 'CustomButtons v2.0.8' (ArgumentNullException: Value cannot be null.
Parameter name: source)
  at System.Linq.Enumerable.Select[TSource,TResult] (System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] selector) [0x0000d] in <30cb9806a8774f11bb35ea6b11076cb4>:0 
  at Oxide.Plugins.CustomButtons.custombuttons_save (ConsoleSystem+Arg arg) [0x0000d] in <048d7490662d4a088ad26e654315d26a>:0 
  at Oxide.Plugins.CustomButtons.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x01441] in <048d7490662d4a088ad26e654315d26a>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <42f9bedc659b4f4786eb778d3cd58968>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000de] in <15f61ddda771464d8246ebdce8ff4811>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <15f61ddda771464d8246ebdce8ff4811>:0 

I'm doing something wrong ?
When i want to save a command nothing is happening

you arent doing anything wrong. its definitely broken. 

i just got a console full of the same spam.