CTW /join button click error

[08:36:27] [Server thread/INFO]: FuneralSuits issued server command: /join
[08:36:29] [Server thread/WARN]: [CTWserver] Task #657 for CTWserver v1.7.0 generated an exception
java.lang.NullPointerException: null
	at org.bukkit.craftbukkit.v1_13_R2.inventory.CraftInventory.setContents(CraftInventory.java:84) ~[patched_1.13.2.jar:git-Paper-636]
	at net.craftersland.ctw.server.utils.StartupKit.giveStartupKit(StartupKit.java:27) ~[?:?]
	at net.craftersland.ctw.server.PlayerHandler$3.run(PlayerHandler.java:94) ~[?:?]
	at org.bukkit.craftbukkit.v1_13_R2.scheduler.CraftTask.run(CraftTask.java:84) ~[patched_1.13.2.jar:git-Paper-636]
	at org.bukkit.craftbukkit.v1_13_R2.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:449) ~[patched_1.13.2.jar:git-Paper-636]
	at net.minecraft.server.v1_13_R2.MinecraftServer.b(MinecraftServer.java:1010) ~[patched_1.13.2.jar:git-Paper-636]
	at net.minecraft.server.v1_13_R2.DedicatedServer.b(DedicatedServer.java:439) ~[patched_1.13.2.jar:git-Paper-636]
	at net.minecraft.server.v1_13_R2.MinecraftServer.a(MinecraftServer.java:940) ~[patched_1.13.2.jar:git-Paper-636]
	at net.minecraft.server.v1_13_R2.MinecraftServer.run(MinecraftServer.java:837) ~[patched_1.13.2.jar:git-Paper-636]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_191]