I'm using the API to give a kit to the player when a condition is met, however when said condition is met nothing happens apart from this gets thrown into the servers console:

Failed to call hook 'OnEnterZone' on plugin 'TestPlugin v0.0.1' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.TestPlugin.OnEnterZone (System.String ZoneID, BasePlayer player) [0x00052] in <abeb0ef471ed4e71ae520c3e82b2bdd3>:0 
  at Oxide.Plugins.TestPlugin.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x000c0] in <abeb0ef471ed4e71ae520c3e82b2bdd3>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <31122a27a2414cd799150f8677cf39d4>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <c2afd8354b8b4f3ca451cf5a1aa111c3>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <c2afd8354b8b4f3ca451cf5a1aa111c3>:0​

I know it says 'OnEnterZone' which is a different plugin but I only get this error when trying to use this plugins GiveKit API. Below is the code that I'm using to try and give the player the kit but its not working; so if im using the API wrong just let me know and ill fix that but otherwise any help would be appreciated (The GiveKit statement is below).

Kits.Call("GiveKit", player, "test");​