Failed to run a 0.10 timer in 'DoorPermissions v2.0.0'

Anyone help me this this if I set a door lock the lock is placed and the permission created and following msg in console...
thanks in advance

Failed to run a 0.10 timer in 'DoorPermissions v2.0.0' 
(NullReferenceException: Object reference not set to an instance of an 
object)
  at Oxide.Plugins.DoorPermissions+DoorObject.AddDoors 
(Oxide.Plugins.DoorPermissions+DoorObject[] doorArray) [0x00013] in :0
at Oxide.Plugins.DoorPermissions+c__AnonStorey4.<>m__0 () [0x0016c] in :0
at Oxide.Core.Libraries.Timer+TimerInstance.FireCallback () [0x00018] in :0

I was able to fix this by making a category and then reloading the plugin