Quicksell Error

[12:22:40] [Server thread/INFO]: Burgerz_ issued server command: /boosters
[12:22:40] [Server thread/ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'boosters' in plugin QuickSell v1.10.7
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at org.bukkit.craftbukkit.v1_8_R1.CraftServer.dispatchCommand(CraftServer.java:645) ~[spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.PlayerConnection.handleCommand(PlayerConnection.java:1115) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.PlayerConnection.a(PlayerConnection.java:950) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(PacketPlayInChat.java:26) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(PacketPlayInChat.java:53) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.PacketHandleTask.run(SourceFile:13) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_25]
	at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:683) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:316) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:623) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:526) [spigot.jar:git-Spigot-c46583f-e6f9fd4]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_25]
Caused by: java.lang.NullPointerException
	at java.lang.String.replace(Unknown Source) ~[?:1.8.0_25]
	at me.mrCookieSlime.CSCoreLibPlugin.Configuration.Variable.apply(Variable.java:26) ~[?:?]
	at me.mrCookieSlime.CSCoreLibPlugin.Configuration.Localization.sendTranslation(Localization.java:68) ~[?:?]
	at me.mrCookieSlime.QuickSell.QuickSell.onCommand(QuickSell.java:265) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot.jar:git-Spigot-c46583f-e6f9fd4]
	... 14 more
[12:22:45] [Server thread/INFO]: Burgerz_ issued server command: /ver QuickSell