Bukkit

What version of the product are you using?
2.1.1

Do you have an error log of what happened?
Seeing this once every few hours:
[SEVERE] Could not pass event PlayerDeathEvent to MoneyDrop v2.1.1
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_5_R3.event.CraftEventFactory.callPlayerDeathEvent(CraftEventFactory.java:340)
    at net.minecraft.server.v1_5_R3.EntityPlayer.die(EntityPlayer.java:293)
    at org.bukkit.craftbukkit.v1_5_R3.entity.CraftLivingEntity.setHealth(CraftLivingEntity.java:77)
    at com.earth2me.essentials.PlayerExtension.setHealth(PlayerExtension.java)
    at com.earth2me.essentials.commands.Commandsuicide.run(Commandsuicide.java:24)
    at com.earth2me.essentials.commands.EssentialsCommand.run(EssentialsCommand.java:105)
    at com.earth2me.essentials.Essentials.onCommandEssentials(Essentials.java:432)
    at com.earth2me.essentials.Essentials.onCommand(Essentials.java:321)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:189)
    at org.bukkit.craftbukkit.v1_5_R3.CraftServer.dispatchCommand(CraftServer.java:523)
    at net.minecraft.server.v1_5_R3.PlayerConnection.handleCommand(PlayerConnection.java:965)
    at net.minecraft.server.v1_5_R3.PlayerConnection.chat(PlayerConnection.java:883)
    at net.minecraft.server.v1_5_R3.PlayerConnection.a(PlayerConnection.java:840)
    at net.minecraft.server.v1_5_R3.Packet3Chat.handle(Packet3Chat.java:44)
    at net.minecraft.server.v1_5_R3.NetworkManager.b(NetworkManager.java:292)
    at net.minecraft.server.v1_5_R3.PlayerConnection.d(PlayerConnection.java:109)
    at net.minecraft.server.v1_5_R3.ServerConnection.b(SourceFile:35)
    at net.minecraft.server.v1_5_R3.DedicatedServerConnection.b(SourceFile:30)
    at net.minecraft.server.v1_5_R3.MinecraftServer.r(MinecraftServer.java:581)
    at net.minecraft.server.v1_5_R3.DedicatedServer.r(DedicatedServer.java:226)
    at net.minecraft.server.v1_5_R3.MinecraftServer.q(MinecraftServer.java:477)
    at net.minecraft.server.v1_5_R3.MinecraftServer.run(MinecraftServer.java:410)
    at net.minecraft.server.v1_5_R3.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.NullPointerException
    at me.drakespirit.plugins.moneydrop.EventListener.onPlayerDeath(EventListener.java:99)
    at sun.reflect.GeneratedMethodAccessor495.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)
    ... 27 more

Please provide any additional information below.
Bukkit-1.5.2-R0.1-1-g53734d2-b2775

Staff edit: Link removed.