[06:52:07 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'f' in plugin Mango v3.2-RELEASE
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at org.bukkit.craftbukkit.v1_8_R1.CraftServer.dispatchCommand(CraftServer.java:646) ~[spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.PlayerConnection.handleCommand(PlayerConnection.java:1115) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.PlayerConnection.a(PlayerConnection.java:950) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(PacketPlayInChat.java:26) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(PacketPlayInChat.java:53) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.PacketHandleTask.run(SourceFile:13) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_112]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_112]
        at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:696) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:316) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:634) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:537) [spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_112]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/util/org/apache/commons/lang3/StringUtils
        at org.zencode.mango.commands.admin.CreateSystemCommand.execute(CreateSystemCommand.java:51) ~[?:?]
        at org.zencode.mango.commands.FactionCommand.execute(FactionCommand.java:114) ~[?:?]
        at org.zencode.mango.utils.command.BaseCommand.onCommand(BaseCommand.java:61) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot-1.8.jar:git-Spigot-550ebac-7019900]
        ... 14 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.util.org.apache.commons.lang3.StringUtils
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:91) ~[spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[spigot-1.8.jar:git-Spigot-550ebac-7019900]
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_112]
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_112]
        at org.zencode.mango.commands.admin.CreateSystemCommand.execute(CreateSystemCommand.java:51) ~[?:?]
        at org.zencode.mango.commands.FactionCommand.execute(FactionCommand.java:114) ~[?:?]
        at org.zencode.mango.utils.command.BaseCommand.onCommand(BaseCommand.java:61) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot-1.8.jar:git-Spigot-550ebac-7019900]
        ... 14 more