[13:44:50] [Server thread/WARN]: [Skript] Task #5 for Skript v2.2-SNAPSHOT generated an exception
java.lang.NoClassDefFoundError: net/minecraft/server/v1_8_R1/GenericAttributes
	at uk.co.umbaska.Enums.Attributes.<clinit>(Attributes.java:10) ~[?:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_31]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_31]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_31]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_31]
	at java.lang.Class.getEnumConstantsShared(Unknown Source) ~[?:1.8.0_31]
	at java.lang.Class.enumConstantDirectory(Unknown Source) ~[?:1.8.0_31]
	at java.lang.Enum.valueOf(Unknown Source) ~[?:1.8.0_31]
	at uk.co.umbaska.Utils.EnumClassInfo$1.parse(EnumClassInfo.java:70) ~[?:?]
	at uk.co.umbaska.Utils.EnumClassInfo$1.parse(EnumClassInfo.java:57) ~[?:?]
	at ch.njol.skript.registrations.Classes.parseSimple(Classes.java:400) ~[?:?]
	at ch.njol.skript.registrations.Classes.parse(Classes.java:429) ~[?:?]
	at ch.njol.skript.lang.UnparsedLiteral.getConvertedExpression(UnparsedLiteral.java:97) ~[?:?]
	at ch.njol.skript.lang.UnparsedLiteral.getConvertedExpression(UnparsedLiteral.java:86) ~[?:?]
	at ch.njol.skript.lang.UnparsedLiteral.getConvertedExpression(UnparsedLiteral.java:1) ~[?:?]
	at ch.njol.skript.effects.EffChange.init(EffChange.java:209) ~[?:?]
	at ch.njol.skript.lang.SkriptParser.parse(SkriptParser.java:244) ~[?:?]
	at ch.njol.skript.lang.SkriptParser.parse(SkriptParser.java:171) ~[?:?]
	at ch.njol.skript.lang.Statement.parse(Statement.java:60) ~[?:?]
	at ch.njol.skript.ScriptLoader.loadItems(ScriptLoader.java:650) ~[?:?]
	at ch.njol.skript.ScriptLoader.loadScript(ScriptLoader.java:510) ~[?:?]
	at ch.njol.skript.ScriptLoader.loadScripts(ScriptLoader.java:245) ~[?:?]
	at ch.njol.skript.ScriptLoader.loadScripts(ScriptLoader.java:199) ~[?:?]
	at ch.njol.skript.Skript$2.run(Skript.java:391) ~[?:?]
	at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71) ~[spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350) [spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:726) [spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367) [spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657) [spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560) [spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_31]
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_8_R1.GenericAttributes
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:91) ~[spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[spigot-1.8.7.jar:git-Spigot-07a5b1b-53433de]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_31]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_31]
	... 31 more