Bukkit

Basically when I startup the server with your plugin, running the latest version, and crafbukkit 1.3.2 r1.0. I get this error and the server crashes:

2012-10-07 09:41:59 [SEVERE] java.lang.NullPointerException
2012-10-07 09:41:59 [SEVERE]     at de.V10lator.RideThaDragon.V10Dragon.d(V10Dragon.java:91)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.EntityLiving.h_(EntityLiving.java:447)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.World.entityJoinedWorld(World.java:1245)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.WorldServer.entityJoinedWorld(WorldServer.java:511)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.World.playerJoinedWorld(World.java:1227)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.World.tickEntities(World.java:1125)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.WorldServer.tickEntities(WorldServer.java:428)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:563)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:213)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:473)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:405)
2012-10-07 09:41:59 [SEVERE]     at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)
2012-10-07 09:41:59 [SEVERE] Encountered an unexpected exception NullPointerException
java.lang.NullPointerException
    at de.V10lator.RideThaDragon.V10Dragon.d(V10Dragon.java:91)
    at net.minecraft.server.EntityLiving.h_(EntityLiving.java:447)
    at net.minecraft.server.World.entityJoinedWorld(World.java:1245)
    at net.minecraft.server.WorldServer.entityJoinedWorld(WorldServer.java:511)
    at net.minecraft.server.World.playerJoinedWorld(World.java:1227)
    at net.minecraft.server.World.tickEntities(World.java:1125)
    at net.minecraft.server.WorldServer.tickEntities(WorldServer.java:428)
    at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:563)
    at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:213)
    at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:473)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:405)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)

Is there any fix? Thanks.

EDIT: Sorry, forget it... I'll have a look into it..

Is the Lifetime in the config higher than 0 and if so is this fixed if you set it to 0?