please help me with this error

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

Time: 05.06.21. 15:54
Description: There was a severe problem during mod loading that has caused the game to fail

cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: DummyCore/Events/DummyEvent_OnClientGUIButtonPress
    at cpw.mods.fml.common.LoadController.transition(LoadController.java:163)
    at cpw.mods.fml.common.Loader.preinitializeMods(Loader.java:559)
    at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:243)
    at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:480)
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:878)
    at net.minecraft.client.main.Main.main(SourceFile:148)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.NoClassDefFoundError: DummyCore/Events/DummyEvent_OnClientGUIButtonPress
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    at java.lang.Class.privateGetPublicMethods(Class.java:2902)
    at java.lang.Class.getMethods(Class.java:1615)
    at cpw.mods.fml.common.eventhandler.EventBus.register(EventBus.java:60)
    at terraWorld.terraBuffs.BT_Mod.preinit(BT_Mod.java:51)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:532)
    at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    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 cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:212)
    at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:190)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    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 cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:119)
    at cpw.mods.fml.common.Loader.preinitializeMods(Loader.java:556)
    ... 10 more
Caused by: java.lang.ClassNotFoundException: DummyCore.Events.DummyEvent_OnClientGUIButtonPress
    at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 42 more
Caused by: java.lang.NullPointerException

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 10 (amd64) version 10.0
    Java Version: 1.8.0_51, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 205076696 bytes (195 MB) / 467963904 bytes (446 MB) up to 4281597952 bytes (4083 MB)
    JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx4G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
    AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
    IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
    FML: MCP v9.05 FML v7.10.99.99 Minecraft Forge 10.13.4.1614 29 mods loaded, 29 mods active
    States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
    UCH    mcp{9.05} [Minecraft Coder Pack] (minecraft.jar) 
    UCH    FML{7.10.99.99} [Forge Mod Loader] (forge-1.7.10-10.13.4.1614-1.7.10.jar) 
    UCH    Forge{10.13.4.1614} [Minecraft Forge] (forge-1.7.10-10.13.4.1614-1.7.10.jar) 
    UCH    Micdoodlecore{} [Micdoodle8 Core] (minecraft.jar) 
    UCH    TooManyItems{1.7.10} [TooManyItems] (minecraft.jar) 
    UCH    debug{1.0} [debug] (denseores-1.6.2.jar) 
    UCH    moEatableSwords{1.7.2} [moSwords Mod Eatables] ([1.7.10]+moSwords+v3b.jar) 
    UCH    moSwords{v3} [Mo Swords Mod] ([1.7.10]+moSwords+v3b.jar) 
    UCE    buffedtools{1.1.1710.1} [Buffed Tools] (BuffedTools-1.1.1710.7.jar) 
    UCH    CarpentersBlocks{3.3.8.2} [Carpenter's Blocks] (Carpenter's+Blocks+v3.3.8.2+-+MC+1.7.10.jar) 
    UCH    craftguide{1.7.1.0} [CraftGuide] (CraftGuide-1.7.1.0-forge.jar) 
    UCH    dldungeonsjdg{1.11.0.1} [Doomlike Dungeons] (DoomlikeDungeons-1.11.0.1-MC1.7.10.jar) 
    UCH    SlimevoidLib{2.0.4.7} [Slimevoid Library] (SlimevoidLibrary-2.0.4.7.jar) 
    UCH    DynamicTransport{0.1.2.0} [Dynamic Transport] (DynamicTransport-0.1.2.0.jar) 
    UCH    FunOres{1.0.3b} [Fun Ores] (FunOres-1.7.10-1.0.3b-12.jar) 
    UCH    GalacticraftCore{3.0.12} [Galacticraft Core] (Galacticraft-Mod-1.7.10.jar) 
    UCH    Mantle{1.7.10-0.3.2.jenkins191} [Mantle] (Mantle-1.7.10-0.3.2b.jar) 
    UCH    mcheli{1.0.2} [MC Helicopter] (mcheli) 
    UCH    minefantasy2{2.8.14.6} [MineFantasyII] (MineFantasyII-2.8.14.6.jar) 
    UCH    morehealth{6.0} [More Health Forge] (More-Health-Enhanced-Mod-1.7.10.zip) 
    UCH    cfm{3.4.7} [§9MrCrayfish's Furniture Mod] (MrCrayfishFurnitureModv3.4.7(1.7.10).jar) 
    UCH    Mystcraft{0.12.3.04} [Mystcraft] (mystcraft-1.7.10-0.12.3.04.jar) 
    UCH    Natura{2.2.0} [Natura] (natura-1.7.10-2.2.1a2.jar) 
    UCH    OreSpawn{1.7.10.20.3} [OreSpawn] (orespawn-1.7.10-20.3.jar) 
    UCH    SpecialMobs{3.2.2} [Special Mobs] (SpecialMobs-1.7.10-3.2.2.jar) 
    UCH    StellarAPI{0.1.3.8} [Stellar API] (Stellar+API-0.1.3.8.jar) 
    UCH    stellarsky{0.1.5.7} [Stellar Sky] (Stellar+Sky-0.1.5.7.jar) 
    UCE    Techguns{0.1.2_alphatest4.1} [Techguns] (Techguns.beta.1.2_alphatest4.1.jar) 
    UCH    denseores{1.0} [Dense Ores] (denseores-1.6.2.jar) 
    GL info: ' Vendor: 'ATI Technologies Inc.' Version: '4.6.14756 Compatibility Profile Context 20.40.40.07 27.20.14040.7001' Renderer: 'AMD Radeon(TM) Graphics'
    Mantle Environment: Environment healthy.