Monster Apocalypse Error #1

16:43:52 [INFO] gamer1097 died
16:44:10 [INFO] gamer1097 issued server command: /kill
16:44:10 [SEVERE] Could not pass event EntityDamageEvent to Monster Apocalypse v
<14.0>
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:427)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62)
        at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredLi
stener.java:30)
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:478)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:463)
        at org.bukkit.command.defaults.KillCommand.execute(KillCommand.java:29)
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:19
0)
        at org.bukkit.craftbukkit.v1_6_R2.CraftServer.dispatchCommand(CraftServe
r.java:527)
        at net.minecraft.server.v1_6_R2.PlayerConnection.handleCommand(PlayerCon
nection.java:979)
        at net.minecraft.server.v1_6_R2.PlayerConnection.chat(PlayerConnection.j
ava:890)
        at net.minecraft.server.v1_6_R2.PlayerConnection.a(PlayerConnection.java
:837)
        at net.minecraft.server.v1_6_R2.Packet3Chat.handle(SourceFile:49)
        at org.spigotmc.netty.NettyNetworkManager.b(NettyNetworkManager.java:230
)
        at net.minecraft.server.v1_6_R2.PlayerConnection.e(PlayerConnection.java
:116)
        at net.minecraft.server.v1_6_R2.ServerConnection.b(SourceFile:37)
        at org.spigotmc.netty.NettyServerConnection.b(NettyServerConnection.java
:125)
        at net.minecraft.server.v1_6_R2.MinecraftServer.t(MinecraftServer.java:5
92)
        at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:2
39)
        at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:4
81)
        at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java
:413)
        at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:5
82)
Caused by: java.lang.NoClassDefFoundError: org/bukkit/craftbukkit/v1_5_R3/entity
/CraftArrow
        at blainicus.MonsterApocalypse.DamageListener.onEntityDamage(DamageListe
ner.java:82)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:425)
        ... 20 more