Have NPC TP and Pathfinding installed as well and am trying to add a tp NPC but sometimes the NPC is not appearing and any time I do /npc_reset i get this error:

Failed to call hook 'cmdChatNPCReset' on plugin 'HumanNPC v0.3.18' (ArgumentException: An item with the same key has already been added. Key: rifle.ak)
  at System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) [0x000c1] in <1f0c1ef1ad524c38bbc5536809c46b48>:0

  at System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) [0x00000] in <1f0c1ef1ad524c38bbc5536809c46b48>:0

  at Oxide.Plugins.HumanNPC.OnServerInitialized () [0x00111] in <3a109cbf6a144baa86e0bab87f483e95>:0

  at Oxide.Plugins.HumanNPC.cmdChatNPCReset (BasePlayer player, System.String command, System.String[] args) [0x00068] in <3a109cbf6a144baa86e0bab87f483e95>:0

  at Oxide.Plugins.HumanNPC.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00be8] in <3a109cbf6a144baa86e0bab87f483e95>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <9affce1cd15c4ec183941adef8db1722>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <4452f821def6406d834e4149849fe7ea>:0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <4452f821def6406d834e4149849fe7ea>:0