NullReferenceException: Object reference not set to an instance of an object

Failed to call hook 'OnPlayerSleep' on plugin 'Hotbars v1.0.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Game.Rust.Cui.CuiHelper.DestroyUi (BasePlayer player, System.String elem) [0x00035] in <68212d1b4e3749dc841d4cc27391f878>:0 
  at Oxide.Plugins.Hotbars.DestroyGUI (BasePlayer player) [0x00000] in <24c767516106490cb437845c374f36ad>:0 
  at Oxide.Plugins.Hotbars.OnPlayerSleep (BasePlayer player) [0x00000] in <24c767516106490cb437845c374f36ad>:0 
  at Oxide.Plugins.Hotbars.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001f9] in <24c767516106490cb437845c374f36ad>: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

Spamming on server load.

Also a request. I use a plugin that activates slots 7 and 8 to put a planner and hammer in them. Is it possible to make it so this plugin ignores those slots?

So I realize my issue with the extra slots is very fringe and not an overall concern for the general public. But is it possible? I'd really like to use this plugin. I know the players would love it. But if it can't be done this is useless to my server with the current setup.

Go ahead and close this. I just got rid of the plugin.

Same problem here. Same exact string of issues on console 

Changed Status from Pending to Closed