Error

[22:32:02 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'b' in plugin ProjectKorra v1.8.0 BETA 1
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot.jar:git-Spigot-fdc1440-53fac9f]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot.jar:git-Spigot-fdc1440-53fac9f]
	at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:641) ~[spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerConnection.java:1162) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:997) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [?:1.7.0_79]
	at java.util.concurrent.FutureTask.run(FutureTask.java:262) [?:1.7.0_79]
	at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:714) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:653) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:556) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at java.lang.Thread.run(Thread.java:745) [?:1.7.0_79]
Caused by: java.lang.NullPointerException
	at com.projectkorra.projectkorra.Commands$1.onCommand(Commands.java:467) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot.jar:git-Spigot-fdc1440-53fac9f]
	... 15 more