Error Message, if player attacks heli

Failed to call hook 'OnEntityTakeDamage' on plugin 'RealPVE v0.1.19' (NullReferenceException: Object reference not set to an instance of an object.)
  at Oxide.Plugins.RealPVE.OnEntityTakeDamage (BaseCombatEntity entity, HitInfo info) [0x0008d] in <8f7bb510a2674b9081ef6adaa25d11d9>:0 8 slprs                                                                           12kb/s in, 88kb/s out
  at Oxide.Plugins.RealPVE.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x01359] in <8f7bb510a2674b9081ef6adaa25d11d9>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <42f9bedc659b4f4786eb778d3cd58968>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000de] in <d59b507fd76240e5b62228d0eae39b73>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <d59b507fd76240e5b62228d0eae39b73>:0
Failed to call hook 'OnEntityTakeDamage' on plugin 'RealPVE v0.1.19' (NullReferenceException: Object reference not set to an instance of an object.)
  at Oxide.Plugins.RealPVE.OnEntityTakeDamage (BaseCombatEntity entity, HitInfo info) [0x0008d] in <8f7bb510a2674b9081ef6adaa25d11d9>:0 8 slprs

Server will fail and I have to reboot.