Error but plugin working

Getting this error and not sure what it means or how to fix. Any advice?

Failed to call hook 'OnServerInitialized' on plugin 'MonumentOwner v1.3.8' (KeyNotFoundException: The given key 'Cargo' was not present in the dictionary.)
  at System.Collections.Generic.Dictionary`2[TKey,TValue].get_Item (TKey key) [0x0001e] in <2161c9885dd04ff291b79db9349c4b9b>:0 
  at Oxide.Plugins.MonumentOwner.OnEntitySpawned (CargoShip cargo) [0x00081] in <9cbc5b1efce845b8acb3286b17cd2b66>:0 
  at Oxide.Plugins.MonumentOwner.OnServerInitialized () [0x00084] in <9cbc5b1efce845b8acb3286b17cd2b66>:0 
  at Oxide.Plugins.MonumentOwner.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00d29] in <9cbc5b1efce845b8acb3286b17cd2b66>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <cd9a02fd331347bd82d550bb1a9c8e9f>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <b76ec77c47d1449e92b2baab8603843d>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <b76ec77c47d1449e92b2baab8603843d>:0 
Loaded plugin MonumentOwner v1.3.8 by jtedal

Probably something happened to the Cargo file which is located in the Data folder. I need more information about what is contained in the Data folder.

I figured it out I had to add in the Cargo file again it was removed somehow

Changed Status from Pending to Closed