It's baaaaaack!
Running Spigot #337 (1.4.5 R1.0)
Running DIabloDrops #363

22:41:08 [SEVERE] Could not pass event EntityDamageByEntityEvent to DiabloDrops v2.2.363
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
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 org.bukkit.craftbukkit.v1_4_5.event.CraftEventFactory.callEvent(CraftEventFactory.java:81)
at org.bukkit.craftbukkit.v1_4_5.event.CraftEventFactory.callEntityDamageEvent(CraftEventFactory.java:367)
at org.bukkit.craftbukkit.v1_4_5.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:389)
at net.minecraft.server.v1_4_5.EntityLiving.damageEntity(EntityLiving.java:658)
at net.minecraft.server.v1_4_5.EntityMonster.damageEntity(EntityMonster.java:39)
at net.minecraft.server.v1_4_5.EntityHuman.attack(EntityHuman.java:794)
at net.minecraft.server.v1_4_5.NetServerHandler.a(NetServerHandler.java:1138)
at net.minecraft.server.v1_4_5.Packet7UseEntity.handle(SourceFile:36)
at net.minecraft.server.v1_4_5.NetworkManager.b(NetworkManager.java:290)
at net.minecraft.server.v1_4_5.NetServerHandler.d(NetServerHandler.java:113)
at net.minecraft.server.v1_4_5.ServerConnection.b(SourceFile:39)
at net.minecraft.server.v1_4_5.DedicatedServerConnection.b(SourceFile:30)
at net.minecraft.server.v1_4_5.MinecraftServer.r(MinecraftServer.java:584)
at net.minecraft.server.v1_4_5.DedicatedServer.r(DedicatedServer.java:222)
at net.minecraft.server.v1_4_5.MinecraftServer.q(MinecraftServer.java:480)
at net.minecraft.server.v1_4_5.MinecraftServer.run(MinecraftServer.java:415)
at net.minecraft.server.v1_4_5.ThreadServerApplication.run(SourceFile:856)
Caused by: java.lang.NullPointerException
at com.modcrafting.diablodrops.effects.EffectsAPI.listEffects(EffectsAPI.java:418)
at com.modcrafting.diablodrops.effects.EffectsAPI.handlePluginEffects(EffectsAPI.java:351)
at com.modcrafting.diablodrops.listeners.EffectsListener.onDiabloMonsterDamageByEntityEvent(EffectsListener.java:46)
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.java:425)
... 20 more

Should be fixed in Build #364.