Error

2013-10-01 23:12:09 [SEVERE] Could not pass event VehicleDamageEvent to SeaBattle v1.5.1
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 net.minecraft.server.v1_6_R3.EntityBoat.damageEntity(EntityBoat.java:104)
at net.minecraft.server.v1_6_R3.EntitySnowball.a(SourceFile:30)
at net.minecraft.server.v1_6_R3.EntityProjectile.l_(EntityProjectile.java:156)
at net.minecraft.server.v1_6_R3.World.entityJoinedWorld(World.java:1354)
at net.minecraft.server.v1_6_R3.World.playerJoinedWorld(World.java:1335)
at net.minecraft.server.v1_6_R3.World.tickEntities(World.java:1223)
at net.minecraft.server.v1_6_R3.WorldServer.tickEntities(WorldServer.java:480)
at net.minecraft.server.v1_6_R3.MinecraftServer.t(MinecraftServer.java:574)
at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:227)
at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:488)
at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java:421)
at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:583)
Caused by: java.lang.NullPointerException
at com.comze_instancelabs.boatgame.Main.onVehicleDamage(Main.java:926)
at sun.reflect.GeneratedMethodAccessor523.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
... 15 more