Probleme lancement Minecraft

Bonjour,
Lorsque je tente de rejoindre un serveur la page reste sur connexion et cour et quand je lance un monde Minecraft minecrat crash :

---- Minecraft Crash Report ----
// Don't do that.

Time: 11/03/14 09:11
Description: Starting integrated server

java.lang.ExceptionInInitializerError
at net.minecraft.server.MinecraftServer.<init>(SourceFile:113)
at btq.<init>(SourceFile:38)
at azl.a(SourceFile:1585)
at bbt.a(SourceFile:202)
at bco.a(SourceFile:172)
at bbt.a(SourceFile:301)
at bco.d(SourceFile:232)
at bco.k(SourceFile:211)
at azl.p(SourceFile:1303)
at azl.ah(SourceFile:757)
at azl.f(SourceFile:711)
at net.minecraft.client.main.Main.main(SourceFile:148)
Caused by: 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 nb.<clinit>(SourceFile:31)
... 12 more
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 net.minecraft.server.MinecraftServer.<init>(SourceFile:113)
at btq.<init>(SourceFile:38)

-- Starting integrated server --
Details:
Level ID: New World-------
Level Name: New World
Stacktrace:
at azl.a(SourceFile:1585)
at bbt.a(SourceFile:202)
at bco.a(SourceFile:172)
at bbt.a(SourceFile:301)
at bco.d(SourceFile:232)
at bco.k(SourceFile:211)

-- Affected screen --
Details:
Screen name: bcw
Stacktrace:
at azl.p(SourceFile:1303)
at azl.ah(SourceFile:757)
at azl.f(SourceFile:711)
at net.minecraft.client.main.Main.main(SourceFile:148)

-- System Details --
Details:
Minecraft Version: 1.7.5
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 169241992 bytes (161 MB) / 207093760 bytes (197 MB) up to 954728448 bytes (910 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
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: 1.7.5
LWJGL: 2.9.1
OpenGL: Intel(R) HD Graphics Family GL version 3.0.0 - Build 8.15.10.2353, Intel
GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

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)
Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Anisotropic Filtering: Off (1)