What is the problem?

[22:42:50] [main/INFO] [STDERR/]: [org.slf4j.helpers.Util:report:128]: SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".

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[22:42:50] [main/INFO] [STDERR/]: [org.slf4j.helpers.Util:report:128]: SLF4J: Defaulting to no-operation (NOP) logger implementation

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[22:42:50] [main/INFO] [STDERR/]: [org.slf4j.helpers.Util:report:128]: SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

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[22:42:50] [main/ERROR] [net.minecraftforge.coremod.transformer.CoreModBaseTransformer/COREMOD]: Error occurred applying transform of coremod META-INF/fieldtomethodtransformers.js function flowingfluidblock

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java.lang.IllegalStateException: Field field_204517_c is not private and an instance field

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at net.minecraftforge.coremod.api.ASMAPI.redirectFieldToMethod(ASMAPI.java:260) ~[coremods-4.0.6.jar:?]

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at jdk.nashorn.internal.scripts.Script$Recompilation$45$776A$\^eval\_$cu1$restOf.initializeCoreMod#transformer-1(<eval>:23) ~[?:?]

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at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:657) ~[jdk.scripting.nashorn:?]

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at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:513) ~[jdk.scripting.nashorn:?]

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at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:527) ~[jdk.scripting.nashorn:?]

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at jdk.nashorn.api.scripting.ScriptObjectMirror.call(ScriptObjectMirror.java:120) ~[jdk.scripting.nashorn:?]

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at net.minecraftforge.coremod.NashornFactory.lambda$getFunction$0(NashornFactory.java:18) ~[coremods-4.0.6.jar:4.0.6+14+master.c21a551]

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at net.minecraftforge.coremod.transformer.CoreModClassTransformer.runCoremod(CoreModClassTransformer.java:18) ~[coremods-4.0.6.jar:?]

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at net.minecraftforge.coremod.transformer.CoreModClassTransformer.runCoremod(CoreModClassTransformer.java:10) ~[coremods-4.0.6.jar:?]

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at net.minecraftforge.coremod.transformer.CoreModBaseTransformer.transform(CoreModBaseTransformer.java:38) ~[coremods-4.0.6.jar:?]

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at cpw.mods.modlauncher.TransformerHolder.transform(TransformerHolder.java:41) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.ClassTransformer.performVote(ClassTransformer.java:179) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:117) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:265) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:136) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:98) ~[modlauncher-8.1.3.jar:?]

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at java.lang.ClassLoader.loadClass(ClassLoader.java:522) ~[?:?]

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at net.minecraft.world.gen.surfacebuilders.SurfaceBuilder.<clinit>(SurfaceBuilder.java:12) ~[?:?]

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at net.minecraft.world.gen.surfacebuilders.ConfiguredSurfaceBuilders.<clinit>(SourceFile:11) ~[?:?]

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at net.minecraft.util.registry.WorldGenRegistries.func_243674_g(WorldGenRegistries.java:34) ~[?:?]

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at net.minecraft.util.registry.WorldGenRegistries.lambda$static$8(WorldGenRegistries.java:90) ~[?:?]

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at java.util.LinkedHashMap.forEach(LinkedHashMap.java:684) ~[?:?]

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at net.minecraft.util.registry.WorldGenRegistries.<clinit>(WorldGenRegistries.java:89) ~[?:?]

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at net.minecraft.util.registry.Registry.<clinit>(Registry.java:465) ~[?:?]

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at net.minecraft.util.registry.Bootstrap.func_151354_b(Bootstrap.java:41) ~[?:?]

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at net.minecraft.server.Main.main(Main.java:142) ~[?:?]

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at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]

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at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]

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at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]

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at java.lang.reflect.Method.invoke(Method.java:566) ~[?:?]

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at net.minecraftforge.fml.loading.FMLServerLaunchProvider.lambda$launchService$0(FMLServerLaunchProvider.java:37) ~[mohist.jar:36.2]

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at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.Launcher.run(Launcher.java:82) ~[modlauncher-8.1.3.jar:?]

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at cpw.mods.modlauncher.Launcher.main(Launcher.java:66) ~[modlauncher-8.1.3.jar:?]

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at net.minecraftforge.server.ServerMain$Runner.runLauncher(ServerMain.java:105) ~[mohist.jar:?]

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at net.minecraftforge.server.ServerMain$Runner.access$100(ServerMain.java:102) ~[mohist.jar:?]

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at net.minecraftforge.server.ServerMain.main(ServerMain.java:86) ~[mohist.jar:?]