[SEVERE] Could not pass event PlayerQuitEvent to DragonAntiPvPLeaver v1.5
org.bukkit.event.EventException
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:341)
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
	at net.minecraft.server.ServerConfigurationManagerAbstract.disconnect(ServerConfigurationManagerAbstract.java:207)
	at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:710)
	at net.minecraft.server.NetworkManager.b(NetworkManager.java:287)
	at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:111)
	at net.minecraft.server.ServerConnection.b(SourceFile:35)
	at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
	at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:579)
	at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:215)
	at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:496)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:428)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:818)
Caused by: java.lang.NoClassDefFoundError: com/massivecraft/factions/struct/FFlag
	at com.github.idragonfire.DragonAntiPvPLeaver.listener.DAntiPvPLeaverListener.onPlayerQuit(DAntiPvPLeaverListener.java:47)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:339)
	... 14 more


ALSO:
[WARNING] [AntiPvPLogger] Task #29 for AntiPvPLogger v0.1 generated an exception
java.lang.NoSuchMethodError: net.minecraft.server.Entity.z()V
	at com.topcat.npclib.NPCManager$1.run(NPCManager.java:64)
	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:532)
	at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:215)
	at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:496)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:428)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:818)