00:04 [Error] Failed to call hook 'OnEntityTakeDamage' on plugin 'RaidAlerts v1.0.1' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.RaidAlerts.OnEntityTakeDamage (BaseCombatEntity entity, HitInfo info) [0x00053] in <598f153bbd794b8fb403e04b113bec8e>:0

  at Oxide.Plugins.RaidAlerts.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00163] in <598f153bbd794b8fb403e04b113bec8e>: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

00:05 [Error] Failed to call hook 'OnEntityTakeDamage' on plugin 'RaidAlerts v1.0.1' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.RaidAlerts.OnEntityTakeDamage (BaseCombatEntity entity, HitInfo info) [0x00053] in <598f153bbd794b8fb403e04b113bec8e>:0

  at Oxide.Plugins.RaidAlerts.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00163] in <598f153bbd794b8fb403e04b113bec8e>: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

Can someone tell us something about the error message? Plese Help