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-434625/

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 ms.<init>(SourceFile:36)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:114)
	at bsg.<init>(SourceFile:38)
	at azb.a(SourceFile:1589)
	at bbg.a(SourceFile:202)
	at bcb.a(SourceFile:172)
	at bbg.a(SourceFile:301)
	at bcb.d(SourceFile:236)
	at bcb.k(SourceFile:211)

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

---- Minecraft Crash Report ----
// Shall we play a game?

Time: 21.10.13 18:50
Description: Updating screen events

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 ms.<init>(SourceFile:36)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:114)
	at bsg.<init>(SourceFile:38)
	at azb.a(SourceFile:1589)
	at bbg.a(SourceFile:202)
	at bcb.a(SourceFile:172)
	at bbg.a(SourceFile:301)
	at bcb.d(SourceFile:236)
	at bcb.k(SourceFile:211)
	at azb.o(SourceFile:1302)
	at azb.ad(SourceFile:755)
	at azb.e(SourceFile:706)
	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)
	... 16 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)
	... 19 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)
	... 28 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 ms.<init>(SourceFile:36)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:114)
	at bsg.<init>(SourceFile:38)
	at azb.a(SourceFile:1589)
	at bbg.a(SourceFile:202)
	at bcb.a(SourceFile:172)
	at bbg.a(SourceFile:301)
	at bcb.d(SourceFile:236)
	at bcb.k(SourceFile:211)

-- Affected screen --
Details:
	Screen name: btf
Stacktrace:
	at azb.o(SourceFile:1302)
	at azb.ad(SourceFile:755)
	at azb.e(SourceFile:706)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w43a
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_21, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 206288144 bytes (196 MB) / 244580352 bytes (233 MB) up to 3817799680 bytes (3640 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx4G
	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: 13w43a
	LWJGL: 2.9.0
	OpenGL: GeForce GT 630/PCIe/SSE2 GL version 4.3.0, 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-434625/20339654/