[Server crashed after going to the Nether. [Crash Report inc.]]

I have reached a dilemma, my server for two people was operating fine until we decided to go into the Nether :/

I have included the crash report, it would be much appreciated if somebody could help me.

 

 

2014-03-13 09:32:38 [sEVERE] [Minecraft-Server] Encountered an unexpected exception NullPointerException

java.lang.NullPointerException

at StevenDimDoors.mod_pocketDim.saving.DDSaveHandler.verifyParents(DDSaveHandler.java:167)

at StevenDimDoors.mod_pocketDim.saving.DDSaveHandler.unpackDimData(DDSaveHandler.java:97)

at StevenDimDoors.mod_pocketDim.saving.DDSaveHandler.loadAll(DDSaveHandler.java:82)

at StevenDimDoors.mod_pocketDim.core.PocketManager.loadInternal(PocketManager.java:436)

at StevenDimDoors.mod_pocketDim.core.PocketManager.load(PocketManager.java:263)

at StevenDimDoors.mod_pocketDim.EventHookContainer.onWorldLoad(EventHookContainer.java:130)

at net.minecraftforge.event.ASMEventHandler_29_EventHookContainer_onWorldLoad_Load.invoke(.dynamic)

at net.minecraftforge.event.ASMEventHandler.invoke(ASMEventHandler.java:39)

at net.minecraftforge.event.EventBus.post(EventBus.java:108)

at net.minecraft.server.MinecraftServer.func_71247_a(MinecraftServer.java:259)

at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:187)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:445)

at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:583)