UltraCosmetics 2.5.7 ERROR

[01:03:07] [Server thread/ERROR]: Error occurred while disabling UltraCosmetics v2.5.7 (Is it up to date?)
java.lang.NullPointerException: null
    at be.isach.ultracosmetics.UltraCosmetics.onDisable(UltraCosmetics.java:238) ~[?:?]
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:266) ~[Spigot.jar:git-Spigot-79a30d7-acbc348]
    at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:361) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:422) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:415) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at org.bukkit.craftbukkit.v1_12_R1.CraftServer.disablePlugins(CraftServer.java:349) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at net.minecraft.server.v1_12_R1.MinecraftServer.stop(MinecraftServer.java:465) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at org.spigotmc.RestartCommand.restart(RestartCommand.java:81) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at org.spigotmc.RestartCommand.restart(RestartCommand.java:40) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at org.spigotmc.RestartCommand$1.run(RestartCommand.java:31) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:758) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:406) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679) [Spigot.jar:git-Spigot-79a30d7-acbc348]
    at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577) [Spigot.jar:git-Spigot-79a30d7-acbc348]