Hopper: java.lang.IllegalStateException: failed to create a child event loop

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-390313/

Crash:

java.lang.IllegalStateException: failed to create a child event loop
	at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:61)
	at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
	at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
	at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
	at mr.<init>(SourceFile:36)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:114)
	at bsb.<init>(SourceFile:38)
	at ayw.a(SourceFile:1579)
	at bbx.e(SourceFile:162)
	at bby.a(SourceFile:214)
	at bar.a(SourceFile:186)
	at bbx.a(SourceFile:187)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// On the bright side, I bought you a teddy bear!

Time: 17.10.13 22:15
Description: Rendering screen

java.lang.IllegalStateException: failed to create a child event loop
	at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:61)
	at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
	at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
	at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
	at mr.<init>(SourceFile:36)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:114)
	at bsb.<init>(SourceFile:38)
	at ayw.a(SourceFile:1579)
	at bbx.e(SourceFile:162)
	at bby.a(SourceFile:214)
	at bar.a(SourceFile:186)
	at bbx.a(SourceFile:187)
	at blc.b(SourceFile:850)
	at ayw.ac(SourceFile:776)
	at ayw.e(SourceFile:700)
	at net.minecraft.client.main.Main.main(SourceFile:103)
Caused by: io.netty.channel.ChannelException: failed to open a new selector
	at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:128)
	at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:120)
	at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:87)
	at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:57)
	... 15 more
Caused by: java.io.IOException: Unable to establish loopback connection
	at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
	at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.nio.ch.PipeImpl.<init>(Unknown Source)
	at sun.nio.ch.SelectorProviderImpl.openPipe(Unknown Source)
	at java.nio.channels.Pipe.open(Unknown Source)
	at sun.nio.ch.WindowsSelectorImpl.<init>(Unknown Source)
	at sun.nio.ch.WindowsSelectorProvider.openSelector(Unknown Source)
	at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:126)
	... 18 more
Caused by: java.net.ConnectException: Connection refused: connect
	at sun.nio.ch.Net.connect0(Native Method)
	at sun.nio.ch.Net.connect(Unknown Source)
	at sun.nio.ch.Net.connect(Unknown Source)
	at sun.nio.ch.SocketChannelImpl.connect(Unknown Source)
	at java.nio.channels.SocketChannel.open(Unknown Source)
	... 27 more


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

-- Head --
Stacktrace:
	at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:61)
	at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
	at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
	at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
	at mr.<init>(SourceFile:36)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:114)
	at bsb.<init>(SourceFile:38)
	at ayw.a(SourceFile:1579)
	at bbx.e(SourceFile:162)
	at bby.a(SourceFile:214)
	at bar.a(SourceFile:186)
	at bbx.a(SourceFile:187)

-- Screen render details --
Details:
	Screen name: bsy
	Mouse location: Scaled: (175, 52). Absolute: (526, 680)
	Screen size: Scaled: (480, 280). Absolute: (1440, 838). Scale factor of 3
Stacktrace:
	at blc.b(SourceFile:850)
	at ayw.ac(SourceFile:776)
	at ayw.e(SourceFile:700)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w42a
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 48027728 bytes (45 MB) / 83062784 bytes (79 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 13w42a
	LWJGL: 2.9.0
	OpenGL: GeForce GTX 280/PCIe/SSE2 GL version 3.3.0, NVIDIA Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: Deutsch (Deutschland)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null
	Anisotropic Filtering: Off (1)

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-390313/18853715/