Bukkit

When a user use a potion give me that errro:

2012-07-14 18:16:11 [SEVERE] Could not pass event PotionSplashEvent to PvPToggle
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:304)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:460)
at org.bukkit.craftbukkit.event.CraftEventFactory.callPotionSplashEvent(CraftEventFactory.java:275)
at net.minecraft.server.EntityPotion.a(EntityPotion.java:80)
at net.minecraft.server.EntityProjectile.F_(EntityProjectile.java:156)
at net.minecraft.server.World.entityJoinedWorld(World.java:1262)
at net.minecraft.server.WorldServer.entityJoinedWorld(WorldServer.java:106)
at net.minecraft.server.World.playerJoinedWorld(World.java:1244)
at net.minecraft.server.World.tickEntities(World.java:1151)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:558)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:459)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
at com.sleelin.pvptoggle.PvPToggle.checkLastAction(PvPToggle.java:341)
at com.sleelin.pvptoggle.listeners.EntityListener.eventMagic(EntityListener.java:97)
at com.sleelin.pvptoggle.listeners.EntityListener.PotionHit(EntityListener.java:74)
at sun.reflect.GeneratedMethodAccessor151.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:302)
... 12 more