HB Error

[WARNING] [Herobrine] Task #5 for Herobrine v4.4 generated an exception
java.lang.NoSuchMethodError: net.minecraft.server.Entity.z()V
	at com.topcat.npclib.NPCManager$1.run(NPCManager.java:61)
	at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:53)
	at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345)
	at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:522)
	at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:215)
	at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:486)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:419)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:818)