Error on /setspawn

Hi i would use this plugin to create Custom Spawnpoints for own Town etc. but i cant setup a sleeping bag which is not near a monument or if i just simple put /setspawn i get an error

(08:51:14) | Failed to run command '/setspawn' on plugin 'SleepingBags'. (ArgumentNullException: Value cannot be null. Parameter name: key)

at System.Collections.Generic.Dictionary`2[TKey,TValue].FindEntry (TKey key) [0x00008] in <f98723dd4586469db5213ec59da723ca>:0

at System.Collections.Generic.Dictionary`2[TKey,TValue].ContainsKey (TKey key) [0x00000] in <f98723dd4586469db5213ec59da723ca>:0

at Oxide.Plugins.SleepingBags.InitializeMonuments () [0x00117] in <49605d7352da4e59a80fc9b59df11c21>:0

at Oxide.Plugins.SleepingBags.AddSpawnLocation (System.String locationName, UnityEngine.Vector3 position, System.Boolean isMonument, BasePlayer player) [0x0006a] in <49605d7352da4e59a80fc9b59df11c21>:0

at Oxide.Plugins.SleepingBags.SetSpawn (BasePlayer player, System.String command, System.String[] args) [0x000cd] in <49605d7352da4e59a80fc9b59df11c21>:0

at Oxide.Game.Rust.Libraries.Command+ChatCommand.HandleCommand (BasePlayer sender, System.String name, System.String[] args) [0x0001b] in <6f267cdce9b243bc982f754214d4280f>:0

at Oxide.Game.Rust.Libraries.Command.HandleChatCommand (BasePlayer sender, System.String name, System.String[] args) [0x00015] in <6f267cdce9b243bc982f754214d4280f>:0

at Oxide.Game.Rust.RustCore.TryRunPlayerCommand (BasePlayer basePlayer, System.String message, System.String commandPrefix) [0x000c2] in <6f267cdce9b243bc982f754214d4280f>:0

For custom locations use /setbag "custom name" 

/setspawn usage is only after you use /setbag command.

If you are using a custom location use /setspawn "same custom name you set for the setbag"