Failed to call hook

any ideas what this means guys. Thanks

Failed to call hook 'cmdpipeopenfilter' on plugin 'JPipes v0.6.9' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.JPipes+jPipe.LookInFilter (BasePlayer player, StorageContainer stash) [0x00000] in <498ae272e7c641b7875fad7b4e653414>:0
at Oxide.Plugins.JPipes+jPipe.OpenFilter (BasePlayer player) [0x0001e] in <498ae272e7c641b7875fad7b4e653414>:0
at Oxide.Plugins.JPipes.cmdpipeopenfilter (ConsoleSystem+Arg arg) [0x00049] in <498ae272e7c641b7875fad7b4e653414>:0
at Oxide.Plugins.JPipes.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00e0e] in <498ae272e7c641b7875fad7b4e653414>: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 <0fbce81d88d64454b3e7abb24df7026b>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <0fbce81d88d64454b3e7abb24df7026b>:0
NullReferenceException: Object reference not set to an instance of an object
at Oxide.Plugins.JPipes+jPipeLogic.Update () [0x0006a] in <53bb0789fc234c17bcf15e7ff5947bfd>:0
(Filename: <53bb0789fc234c17bcf15e7ff5947bfd> Line: 0)