What I expected to happen was...:
Open my world :/

What actually happened was...:
I downloaded a map of mine from a friend's computer that I played 1.9 on, then I rtansfered that world to mine. I opened it and it gave me that error.

Steps to Reproduce:
1: Open a world.
2: It fails.

Crash log:
---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 3/10/16 5:43 PM
Description: Updating screen events

java.lang.IllegalStateException: failed to create a child event loop
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:68)
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 ma$1.a(SourceFile:61)
at ma$1.b(SourceFile:58)
at oj.c(SourceFile:10)
at ma.a(SourceFile:138)
at bcf.a(SourceFile:2135)
at bhn.e(SourceFile:227)
at bhn.a(SourceFile:182)
at bhn.a(SourceFile:154)
at bdl.b(SourceFile:41)
at bhm.a(SourceFile:118)
at bfb.k(SourceFile:404)
at bhm.k(SourceFile:50)
at bfb.p(SourceFile:381)
at bcf.t(SourceFile:1575)
at bcf.av(SourceFile:962)
at bcf.a(SourceFile:392)
at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: io.netty.channel.ChannelException: failed to open a new selector
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:128)
at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:120)
at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:87)
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:64)
... 20 more
Caused by: java.io.IOException: Unable to establish loopback connection
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:101)
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:68)
at java.security.AccessController.doPrivileged(Native Method)
at sun.nio.ch.PipeImpl.<init>(PipeImpl.java:170)
at sun.nio.ch.SelectorProviderImpl.openPipe(SelectorProviderImpl.java:50)
at java.nio.channels.Pipe.open(Pipe.java:155)
at sun.nio.ch.WindowsSelectorImpl.<init>(WindowsSelectorImpl.java:127)
at sun.nio.ch.WindowsSelectorProvider.openSelector(WindowsSelectorProvider.java:44)
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:126)
... 23 more
Caused by: java.net.SocketException: Permission denied: listen
at sun.nio.ch.Net.listen(Native Method)
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:215)
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:67)
at sun.nio.ch.PipeImpl$Initializer$LoopbackConnector.run(PipeImpl.java:124)
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:83)
... 31 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:68)
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 ma$1.a(SourceFile:61)
at ma$1.b(SourceFile:58)
at oj.c(SourceFile:10)
at ma.a(SourceFile:138)
at bcf.a(SourceFile:2135)
at bhn.e(SourceFile:227)
at bhn.a(SourceFile:182)
at bhn.a(SourceFile:154)
at bdl.b(SourceFile:41)
at bhm.a(SourceFile:118)
at bfb.k(SourceFile:404)
at bhm.k(SourceFile:50)
at bfb.p(SourceFile:381)

– Affected screen –
Details:
Screen name: bez
Stacktrace:
at bcf.t(SourceFile:1575)
at bcf.av(SourceFile:962)
at bcf.a(SourceFile:392)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.9
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 51219368 bytes (48 MB) / 218755072 bytes (208 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
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
Launched Version: 1.9
LWJGL: 2.9.4
OpenGL: Intel(R) HD Graphics Family GL version 3.1.0 - Build 8.15.10.2622, Intel
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs:
Current Language: English (US)
Profiler Position: N/A (disabled)
CPU: 4x Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz