Failed to call hook 'OnHammerHit' on plugin 'JPipes v0.6.10' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.JPipes.checkpipeoverlap (System.Collections.Generic.Dictionary`2[TKey,TValue] rps, Oxide.Plugins.JPipes+jPipeData data) [0x00011] in <d05dedace1914c728b190a215e574c4a>:0
  at Oxide.Plugins.JPipes.NewPipe (BasePlayer player, Oxide.Plugins.JPipes+UserInfo userinfo) [0x0003b] in <d05dedace1914c728b190a215e574c4a>:0
  at Oxide.Plugins.JPipes.OnHammerHit (BasePlayer player, HitInfo hit) [0x0016b] in <d05dedace1914c728b190a215e574c4a>:0
  at Oxide.Plugins.JPipes.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0048a] in <d05dedace1914c728b190a215e574c4a>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <60c318df79ed41688ea59335e48d61ad>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <9882f28dc2204b4dba514a9ad18f5042>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <9882f28dc2204b4dba514a9ad18f5042>:0

can any on help me 

Same issue

Same here.

I wouldn't go holding your breath waiting for this to get fixed ...... 

This plugin is no longer maintained. Use syncPipes instead.