Throwing errors with OnUserGroupAdded hoom

Failed to call hook 'OnUserGroupAdded' on plugin 'BPUnlock v1.0.6' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.BPUnlock.UpdatePlayerBlueprints (BasePlayer player) [0x00087] in <16ea433508dd41b89808530cf8da6a8a>:0 
  at Oxide.Plugins.BPUnlock.OnUserGroupAdded (System.String id, System.String groupName) [0x00019] in <16ea433508dd41b89808530cf8da6a8a>:0 
  at Oxide.Plugins.BPUnlock.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0008d] in <16ea433508dd41b89808530cf8da6a8a>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <60c318df79ed41688ea59335e48d61ad>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <50629aa0e75d4126b345d8d9d64da28d>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <50629aa0e75d4126b345d8d9d64da28d>:0


update: the error that occurs seems to be placed allready before, the plugin isnt able to handle the Update Timer for the AddQueueManager in the plugin so that seems to be the problem (we were not able to update blueprints of players)

update2: was an error with an item in bpunlock which is not longer a blueprint - so selfmade problem, can be closed, sry