2013-08-04 12:19:11 [SEVERE] Exception in command handler (Report this on github unless you did something dumb like enter letters as numbers):
java.lang.IllegalArgumentException: Duplicate id value for 7!
at ODataWatcher.a(SourceFile:60)
at OEntityLivingBase.a(OEntityLivingBase.java:88)
at OEntityLiving.a(OEntityLiving.java:91)
at OEntityZombie.a(SourceFile:72)
at Mob.<init>(Mob.java:39)
at Mob.<init>(Mob.java:51)
at PlayerCommands$23.execute(PlayerCommands.java:1218)
at BaseCommand.parseCommand(BaseCommand.java:36)
at PlayerCommands.parsePlayerCommand(PlayerCommands.java:32)
at Player.command(Player.java:207)
at Player.chat(Player.java:132)
at ONetServerHandler.a(ONetServerHandler.java:625)
at OPacket3Chat.a(OPacket3Chat.java:45)
at OTcpConnection.b(SourceFile:354)
at ONetServerHandler.e(ONetServerHandler.java:44)
at ONetworkListenThread.b(SourceFile:37)
at ODedicatedServerListenThread.b(SourceFile:30)
at OMinecraftServer.t(OMinecraftServer.java:482)
at ODedicatedServer.t(SourceFile:262)
at OMinecraftServer.s(OMinecraftServer.java:392)
at OMinecraftServer.run(OMinecraftServer.java:331)
at OThreadMinecraftServer.run(SourceFile:582)
/spawnmob Zombie (same for other mobs):