Failed to call hook 'OnServerInitialized' on plugin 'HarvestBlockSafeZone v1.0.1' (NullReferenceException: )
  at (wrapper managed-to-native) UnityEngine.GameObject.Internal_AddComponentWithType(UnityEngine.GameObject,System.Type)
  at UnityEngine.GameObject.AddComponent (System.Type componentType) [0x00001] in <c8dc2b468d1841099baa4dd8a110cc44>:0 
  at UnityEngine.GameObject.AddComponent[T] () [0x00001] in <c8dc2b468d1841099baa4dd8a110cc44>:0 
  at Oxide.Plugins.HarvestBlockSafeZone.OnServerInitialized () [0x00000] in <3b8776b2233b417892e098cd9b7ccaae>:0 
  at Oxide.Plugins.HarvestBlockSafeZone.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00032] in <3b8776b2233b417892e098cd9b7ccaae>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <e23ba2c0f246426296d81c842cbda3af>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <50629aa0e75d4126b345d8d9d64da28d>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <50629aa0e75d4126b345d8d9d64da28d>:0 

This should be fixed, please update to 1.0.2