Crash Report (custom modpack, this is the only mod added between the last time it worked and the first time it didn't)

[enderlord99]

---- Minecraft Crash Report ---- // Why is it breaking :(

Time: 9/29/15 6:04 PM Description: Exception in server tick loop

java.lang.NoClassDefFoundError: codechicken/nei/NEIServerConfig at codechicken.nei.ServerHandler.loadEvent(ServerHandler.java:45) at cpw.mods.fml.common.eventhandler.ASMEventHandler_218_ServerHandler_loadEvent_Load.invoke(.dynamic) at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54) at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:138) at net.minecraft.server.integrated.IntegratedServer.func_71247_a(IntegratedServer.java:73) at net.minecraft.server.integrated.IntegratedServer.func_71197_b(IntegratedServer.java:92) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:387) at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)

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

-- System Details -- Details: Minecraft Version: 1.7.10 Operating System: Windows 8.1 (amd64) version 6.3 Java Version: 1.8.0_40, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 449629280 bytes (428 MB) / 826277888 bytes (788 MB) up to 954728448 bytes (910 MB) JVM Flags: 3 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xms512m -Xmx1024m AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used IntCache: cache: 0, tcache: 16, allocated: 29, tallocated: 77 FML: MCP v9.05 FML v7.10.99.99 Minecraft Forge 10.13.4.1492 34 mods loaded, 34 mods active States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored UCHIJAA mcp{9.05} Minecraft Coder Pack UCHIJAA FML{7.10.99.99} Forge Mod Loader UCHIJAA Forge{10.13.4.1492} Minecraft Forge UCHIJAA CodeChickenCore{1.0.4.29} CodeChicken Core UCHIJAA NotEnoughItems{1.0.3.74} Not Enough Items UCHIJAA {000} CoFH ASM UCHIJAA bspkrsCore{6.16} bspkrsCore UCHIJAA FloatingRuins{1.7.10.r02} FloatingRuins UCHIJAA StartingInventory{1.7.10.r03} StartingInventory UCHIJAA Apocalypse{0.0.6} §cApocalypse§r UCHIJAA BattleTowers{1.5.1} Battle Towers UCHIJAA CoFHCore{1.7.10R3.0.3} CoFH Core UCHIJAA CustomSpawner{3.3.0} [DrZhark's CustomSpawner](CustomMobSpawner 3.3.0.jar.zip) UCHIJAA DeadlyWorld{1.0.2} Deadly World UCHIJAA dldungeonsjdg{1.8.5} Doomlike Dungeons UCHIJAA MoCreatures{6.3.1} [DrZhark's Mo'Creatures Mod](DrZharks MoCreatures Mod v6.3.1.zip) UCHIJAA EnderIO{1.7.10-2.2.8.381} Ender IO UCHIJAA EnderStorage{1.4.5.27} EnderStorage UCHIJAA EnderZoo{1.7.10-1.0.15.32} Ender Zoo UCHIJAA Baubles{1.0.1.10} Baubles UCHIJAA ExtraUtilities{1.2.11} Extra Utilities UCHIJAA journeymap{@JMVERSION@} JourneyMap UCHIJAA Mantle{1.7.10-0.3.2.jenkins184} Mantle UCHIJAA MineTweaker3{3.0.10} MineTweaker 3 UCHIJAA Natura{2.2.0} Natura UCHIJAA netherblocker{1.7.10-1.0} Nether Blocker UCHIJAA onechunkchallenge{${version}} One Chunk Challenge UCHIJAA Roguelike{1.3.4} Roguelike Dungeons UCHIJAA AS_Ruins{14.7} Ruins Spawning System UCHIJAA TConstruct{1.7.10-1.8.7.build979} Tinkers' Construct UCHIJAA Thaumcraft{4.2.3.5} Thaumcraft UCHIJAA ThaumicHorizons{1.1.5} Thaumic Horizons UCHIJAA voiddecay{1.0.10} VoidDecay UCHIJAA aobd{2.8.4} Another One Bites The Dust GL info: ERROR RuntimeException: No OpenGL context found in the current thread. CoFHCore: -[1.7.10]3.0.3-303 Mantle Environment: Environment healthy. TConstruct Environment: Environment healthy. Profiler Position: N/A (disabled) Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used Player Count: 0 / 8; [] Type: Integrated Server (map_client.txt) Is Modded: Definitely; Client brand changed to 'fml,forge'

[Yopu]

After searching around still couldn't find the direct cause. Try updating NEI to the latest builds and see if it solves it.