Server Crash [FTB Ultimate Server]

[Tristan McDonnor]

I changed it to allow flight on the server, in the server properties and after that my server keeps crashing even when I changed it back, so I dont know whats going on here is my crash report:

---- Minecraft Crash Report ----
// Surprise! Haha. Well, this is awkward.

Time: 4/24/13 6:23 PM
Description: Exception in server tick loop

java.lang.NullPointerException
at codechicken.xycraftcopy.core.world.WorldExtensionManager.preTick(WorldExtensionManager.java:242)
at codechicken.xycraftcopy.core.world.WorldExtensionManager.access$400(WorldExtensionManager.java:25)
at codechicken.xycraftcopy.core.world.WorldExtensionManager$WorldExtensionServerTickHandler.tickStart(WorldExtensionManager.java:157)
at cpw.mods.fml.common.SingleIntervalHandler.tickStart(SingleIntervalHandler.java:16)
at cpw.mods.fml.common.FMLCommonHandler.tickStart(FMLCommonHandler.java:120)
at cpw.mods.fml.common.FMLCommonHandler.onPreWorldTick(FMLCommonHandler.java:296)
at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:664)
at ho.r(DedicatedServer.java:269)
at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:599)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)
at fy.run(SourceFile:849)