16:34:19 [SEVERE] com.sk89q.minecraft.util.commands.WrappedCommandException: jav
a.lang.LinkageError: loader constraint violation: when resolving method "com.sk8
9q.worldguard.protection.flags.Flag.getRegionGroupFlag()Lcom/sk89q/worldguard/pr
otection/flags/RegionGroupFlag;" the class loader (instance of org/bukkit/plugin
/java/PluginClassLoader) of the current class, com/sk89q/worldguard/bukkit/comma
nds/RegionPrintoutBuilder, and the class loader (instance of org/bukkit/plugin/j
ava/PluginClassLoader) for resolved class, com/sk89q/worldguard/protection/flags
/Flag, have different Class objects for the type q.worldguard.protection.flags.F
lag.getRegionGroupFlag()Lcom/sk89q/worldguard/protection/flags/RegionGroupFlag;
used in the signature
16:34:19 [SEVERE]       at com.sk89q.minecraft.util.commands.CommandsManager.inv
okeMethod(CommandsManager.java:543)
16:34:19 [SEVERE]       at com.sk89q.minecraft.util.commands.CommandsManager.exe
cuteMethod(CommandsManager.java:520)
16:34:19 [SEVERE]       at com.sk89q.minecraft.util.commands.CommandsManager.exe
cuteMethod(CommandsManager.java:475)
16:34:19 [SEVERE]       at com.sk89q.minecraft.util.commands.CommandsManager.exe
cute(CommandsManager.java:409)
16:34:19 [SEVERE]       at com.sk89q.worldguard.bukkit.WorldGuardPlugin.onComman
d(WorldGuardPlugin.java:232)
16:34:19 [SEVERE]       at com.sk89q.bukkit.util.DynamicPluginCommand.execute(Dy
namicPluginCommand.java:52)
16:34:19 [SEVERE]       at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCo
mmandMap.java:190)
16:34:19 [SEVERE]       at org.bukkit.craftbukkit.v1_6_R2.CraftServer.dispatchCo
mmand(CraftServer.java:527)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.PlayerConnection.handleC
ommand(PlayerConnection.java:981)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.PlayerConnection.chat(Pl
ayerConnection.java:892)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.PlayerConnection.a(Playe
rConnection.java:839)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.Packet3Chat.handle(Sourc
eFile:49)
16:34:19 [SEVERE]       at org.spigotmc.netty.NettyNetworkManager.b(NettyNetwork
Manager.java:230)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.PlayerConnection.e(Playe
rConnection.java:118)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.ServerConnection.b(Sourc
eFile:37)
16:34:19 [SEVERE]       at org.spigotmc.netty.NettyServerConnection.b(NettyServe
rConnection.java:125)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.MinecraftServer.t(Minecr
aftServer.java:592)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.DedicatedServer.t(Dedica
tedServer.java:239)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.MinecraftServer.s(Minecr
aftServer.java:481)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.MinecraftServer.run(Mine
craftServer.java:413)
16:34:19 [SEVERE]       at net.minecraft.server.v1_6_R2.ThreadServerApplication.
run(SourceFile:582)
16:34:19 [SEVERE] Caused by: java.lang.LinkageError: loader constraint violation
: when resolving method "com.sk89q.worldguard.protection.flags.Flag.getRegionGro
upFlag()Lcom/sk89q/worldguard/protection/flags/RegionGroupFlag;" the class loade
r (instance of org/bukkit/plugin/java/PluginClassLoader) of the current class, c
om/sk89q/worldguard/bukkit/commands/RegionPrintoutBuilder, and the class loader
(instance of org/bukkit/plugin/java/PluginClassLoader) for resolved class, com/s
k89q/worldguard/protection/flags/Flag, have different Class objects for the type
 q.worldguard.protection.flags.Flag.getRegionGroupFlag()Lcom/sk89q/worldguard/pr
otection/flags/RegionGroupFlag; used in the signature
16:34:19 [SEVERE]       at com.sk89q.worldguard.bukkit.commands.RegionPrintoutBu
ilder.appendFlagsList(RegionPrintoutBuilder.java:117)
16:34:19 [SEVERE]       at com.sk89q.worldguard.bukkit.commands.RegionCommands.f
lag(RegionCommands.java:924)
16:34:19 [SEVERE]       at sun.reflect.NativeMethodAccessorImpl.invoke0(Native M
ethod)
16:34:19 [SEVERE]       at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown S
ource)
16:34:19 [SEVERE]       at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unkno
wn Source)
16:34:19 [SEVERE]       at java.lang.reflect.Method.invoke(Unknown Source)
16:34:19 [SEVERE]       at com.sk89q.minecraft.util.commands.CommandsManager.inv
okeMethod(CommandsManager.java:533)
16:34:19 [SEVERE]       ... 20 more