Making a new one to show the exact line that has the error
[21:18:37] [Server thread/FATAL] [FML]: The following problems were captured during this phase
[21:18:37] [Server thread/ERROR] [FML]: Caught exception from silkspawners (silkspawners)
java.lang.NoClassDefFoundError: com/EvilNotch/lib/util/minecraft/MinecraftUtil
at com.EvilNotch.silkspawners.MainJava.worldLoad(MainJava.java:82) ~[MainJava.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_25]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_25]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_25]
at java.lang.reflect.Method.invoke(Method.java:483) ~[?:1.8.0_25]
at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:600) ~[forge-1.12.2-14.23.3.2673.jar:?]
at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_25]
at java.lang.reflect.Method.invoke(Method.java:483) ~[?:1.8.0_25]
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76) ~[guava-21.0.jar:?]
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116) ~[guava-21.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:217) ~[guava-21.0.jar:?]
at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:280) ~[LoadController.class:?]
at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:258) [LoadController.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_25]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_25]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_25]
at java.lang.reflect.Method.invoke(Method.java:483) ~[?:1.8.0_25]
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76) ~[guava-21.0.jar:?]
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71) ~[guava-21.0.jar:?]
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116) ~[guava-21.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:217) ~[guava-21.0.jar:?]
at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:149) [LoadController.class:?]
at net.minecraftforge.fml.common.Loader.serverStarting(Loader.java:806) [Loader.class:?]
at net.minecraftforge.fml.common.FMLCommonHandler.handleServerStarting(FMLCommonHandler.java:296) [FMLCommonHandler.class:?]
at net.minecraft.server.integrated.IntegratedServer.func_71197_b(IntegratedServer.java:158) [chd.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:484) [MinecraftServer.class:?]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]
Caused by: java.lang.ClassNotFoundException: com.EvilNotch.lib.util.minecraft.MinecraftUtil
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_25]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_25]
... 35 more
Caused by: java.lang.NullPointerException
[21:18:37] [Server thread/ERROR] [FML]: A fatal exception occurred during the server starting event
net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from silkspawners (silkspawners)

This is officially something on your end.

in the future use pastebin or gist for crash reports

use evil notch lib release not the beta please. I am closing this but, if it still persists tell me I will re-open I am aware of this issue.

I re-organized the packages thus resulting in silkspawners not being able to find the class it was compiled with.

No need for comments issue is fixed next release