Sponge compatibility with Overlord mod

(I’m french, excuse my english)

Hi,

I run a server forge with spongeforge-1.10.2-2107-6.0.0-BETA-1865, but it seems to not be compatible with the mod Overlord.
About Overlord : https://mods.curse.com/mc-mods/minecraft/251732-overlord

here the crash report :

---- Minecraft Crash Report ----

WARNING: coremods are present:
  SpongeCoremod (spongeforge-1.10.2-2107-6.0.0-BETA-1865.jar)
Contact their authors BEFORE contacting forge

// You should try our sister game, Minceraft!

Time: 02/11/16 22:02
Description: Exception in server tick loop

net.minecraftforge.fml.common.LoaderException: java.lang.ExceptionInInitializerError
	at net.minecraftforge.fml.common.LoadController.transition(LoadController.java:186)
	at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:797)
	at net.minecraftforge.fml.server.FMLServerHandler.finishServerLoading(FMLServerHandler.java:107)
	at net.minecraftforge.fml.common.FMLCommonHandler.onServerStarted(FMLCommonHandler.java:333)
	at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:214)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:431)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ExceptionInInitializerError
	at the_fireplace.overlord.Overlord.init(Overlord.java:126)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:600)
	at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
	at com.google.common.eventbus.EventBus.post(EventBus.java:275)
	at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:239)
	at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:217)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
	at com.google.common.eventbus.EventBus.post(EventBus.java:275)
	at net.minecraftforge.fml.common.LoadController.redirect$onPost$zzd000(LoadController.java:53)
	at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:142)
	at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:795)
	... 5 more
Caused by: java.lang.NullPointerException
	at java.io.File.<init>(Unknown Source)
	at net.minecraft.world.storage.SaveHandler.<init>(SaveHandler.java:37)
	at net.minecraft.world.chunk.storage.AnvilSaveHandler.<init>(AnvilSaveHandler.java:18)
	at net.minecraft.world.chunk.storage.AnvilSaveConverter.func_75804_a(SourceFile:83)
	at org.spongepowered.common.world.WorldManager.getCurrentSavesDirectory(WorldManager.java:76)
	at net.minecraftforge.common.DimensionManager.getCurrentSaveRootDirectory(DimensionManager.java:274)
	at the_fireplace.overlord.tools.Alliances.<clinit>(Alliances.java:15)
	... 33 more


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
	Minecraft Version: 1.10.2
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_101, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 335006352 bytes (319 MB) / 1084751872 bytes (1034 MB) up to 1908932608 bytes (1820 MB)
	JVM Flags: 1 total; -Xmx2048M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	FML: MCP 9.32 Powered by Forge 12.18.2.2107 21 mods loaded, 21 mods active
	States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
	UCHI	mcp{9.19} [Minecraft Coder Pack] (minecraft.jar) 
	UCHI	FML{8.0.99.99} [Forge Mod Loader] (forge-1.10.2-12.18.2.2107-universal.jar) 
	UCHI	Forge{12.18.2.2107} [Minecraft Forge] (forge-1.10.2-12.18.2.2107-universal.jar) 
	UCHI	spongeapi{6.0.0-SNAPSHOT-167fe7b} [SpongeAPI] (minecraft.jar) 
	UCHI	sponge{1.10.2-2107-6.0.0-BETA-1865} [SpongeForge] (spongeforge-1.10.2-2107-6.0.0-BETA-1865.jar) 
	UCHI	ForgeEndertech{1.1.1.1} [Forge Endertech] (ForgeEndertech-1.10.2-1.1.1.1.jar) 
	UCHI	AdHooks{1.10.2-1.0.0.2} [Advanced Hook Launchers] (AdHooks-1.10.2-1.0.0.2.jar) 
	UCHI	ambientsounds{1.2.0} [AmbientSounds] (AmbientSounds v1.2.1 mc1.10.2.zip) 
	UCHI	chestmaker{2.0.0} [ChestMaker] (ChestMaker-2.7.1.jar) 
	UCHI	DungeonTactics{DT0.9.5} [DungeonTactics] (DungeonTactics-1.10.2-0.9.5.jar) 
	UCHI	io.github.hsyyid.essentialcmds{@project.informativeVersion@} [EssentialCmds] (EssentialCmds-1.10.2-8.1.14-universal.jar) 
	UCHI	IronChest{7.0.7.795} [Iron Chest] (ironchest-1.10.2-7.0.7.795.jar) 
	UCHI	KaishiWeapons{v0.1} [Kaishi's Weapons Pack] (KaishiWeapons-1.9.4.jar) 
	UCHI	mithwoodforest{RMF1.02} [Rainbeau's Mithwood Forest] (MithwoodForest-RMF1.02-MC1.10.2.jar) 
	UCHE	overlord{1.1.3} [Overlord] (Overlord-1.1.3.jar) 
	UCHI	pcb{1.5.0} [Portable Craft Bench] (Portable-Craft-Bench-Mod-1.10.2.jar) 
	UCHI	corerm{1.2e-1.9.4} [RikMuld's Core] (RikMuldsCore_1.2e-1.10.2.jar) 
	UCHI	roughMobs{1.0} [Rough Mobs] (Rough-Mobs-Mod-1.10.2.jar) 
	UCHI	rtg{1.10.2} [Realistic Terrain Generation] (RTG-1.10.2-4.1.1.2-snapshot-1.jar) 
	UCHI	camping{2.3d-1.9.4} [The Camping Mod 2] (TheCampingMod_2.3d-1.10.2.jar) 
	UCHI	treechopper{1.0.3a} [Tree Chopper] (TreeChopper-1.0.3a.jar) 
	Loaded coremods (and transformers): 
SpongeCoremod (spongeforge-1.10.2-2107-6.0.0-BETA-1865.jar)
  org.spongepowered.common.launch.transformer.SpongeSuperclassTransformer
	Profiler Position: N/A (disabled)
	Is Modded: Definitely; Server brand changed to 'fml,forge,sponge'
	Type: Dedicated Server (map_server.txt) 

Does it possible to solve this problem ?

Thank you in advance for your help.

that error is not very helpful, update to the latest version of Overlord (1.1.3 is way old as 1.3.5 is the latest) and if it crashes again it will be easier to find the issue