Problem Server crashes during startup

[Myst]

I just started making servers and when it was doing the loading everything I got a crash report saying:
---- Minecraft Crash Report ----
// Ooh. Shiny.
Description: Exception in server tick loop

java.lang.NullPointerException
at org.bukkit.craftbukkit.CraftChunk.getWorld(CraftChunk.java:70)
at org.bukkit.event.world.ChunkEvent.<init>(ChunkEvent.java:12)
at org.bukkit.event.world.ChunkPopulateEvent.<init>(ChunkPopulateEvent.java:16)
at keepcalm.mods.bukkit.forgeHandler.ForgeEventHandler.populateChunks(ForgeEventHandler.java:925)
at net.minecraftforge.event.ASMEventHandler_124_ForgeEventHandler_populateChunks_Post.invoke(.dynamic)
at net.minecraftforge.event.ASMEventHandler.invoke(ASMEventHandler.java:35)
at net.minecraftforge.event.EventBus.post(EventBus.java:103)
at abb.a(ChunkProviderGenerate.java:601)
at im.a(ChunkProviderServer.java:258)
at zz.a(Chunk.java:1258)
at im.c(ChunkProviderServer.java:153)
at net.minecraft.server.MinecraftServer.e(MinecraftServer.java:310)
at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:284)
at ho.c(DedicatedServer.java:180)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:458)
at fy.run(SourceFile:849)
As you can see I don't know much but, help!