I keep on getting this error:
[18:11:06 ERROR]: java.io.IOException: Stream closed
[18:11:06 ERROR]: Game ended with bad state (exit code 1)
Here is the important part of the Developement Console, I hope:

[18:11:03 INFO]: Finished downloading /Users/hela/Library/Application Support/minecraft/versions/1.7.4/1.7.4.jar for job 'Version & Libraries': Used own copy as it matched etag
[18:11:03 INFO]: Job 'Version & Libraries' finished successfully (took 0:00:00.465)
[18:11:03 INFO]: Launching game
[18:11:03 INFO]: Looking for old natives & assets to clean up...
[18:11:03 INFO]: Unpacking natives to /Users/hela/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1393283463447201000
[18:11:03 INFO]: Launching in /Users/hela/Library/Application Support/minecraft/Profiles/x_NINJA_
[18:11:03 INFO]: Half command: /System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home/bin/java -Xdock:icon=/Users/hela/Library/Application Support/minecraft/assets/objects/99/991b421dfd401f115241601b2b373140a8d78572 -Xdock:name=Minecraft -Xmx1G -Djava.library.path=/Users/hela/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1393283463447201000 -cp /Users/hela/Library/Application Support/minecraft/libraries/java3d/vecmath/1.3.1/vecmath-1.3.1.jar:/Users/hela/Library/Application Support/minecraft/libraries/net/sf/trove4j/trove4j/3.0.3/trove4j-3.0.3.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/ibm/icu/icu4j-core-mojang/51.2/icu4j-core-mojang-51.2.jar:/Users/hela/Library/Application Support/minecraft/libraries/net/sf/jopt-simple/jopt-simple/4.5/jopt-simple-4.5.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/paulscode/codecjorbis/20101023/codecjorbis-20101023.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/paulscode/codecwav/20101023/codecwav-20101023.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/paulscode/libraryjavasound/20101123/libraryjavasound-20101123.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/paulscode/librarylwjglopenal/20100824/librarylwjglopenal-20100824.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/paulscode/soundsystem/20120107/soundsystem-20120107.jar:/Users/hela/Library/Application Support/minecraft/libraries/io/netty/netty-all/4.0.10.Final/netty-all-4.0.10.Final.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/google/guava/guava/15.0/guava-15.0.jar:/Users/hela/Library/Application Support/minecraft/libraries/org/apache/commons/commons-lang3/3.1/commons-lang3-3.1.jar:/Users/hela/Library/Application Support/minecraft/libraries/commons-io/commons-io/2.4/commons-io-2.4.jar:/Users/hela/Library/Application Support/minecraft/libraries/net/java/jinput/jinput/2.0.5/jinput-2.0.5.jar:/Users/hela/Library/Application Support/minecraft/libraries/net/java/jutils/jutils/1.0.0/jutils-1.0.0.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/google/code/gson/gson/2.2.4/gson-2.2.4.jar:/Users/hela/Library/Application Support/minecraft/libraries/com/mojang/authlib/1.2/authlib-1.2.jar:/Users/hela/Library/Application Support/minecraft/libraries/org/apache/logging/log4j/log4j-api/2.0-beta9/log4j-api-2.0-beta9.jar:/Users/hela/Library/Application Support/minecraft/libraries/org/apache/logging/log4j/log4j-core/2.0-beta9/log4j-core-2.0-beta9.jar:/Users/hela/Library/Application Support/minecraft/libraries/org/lwjgl/lwjgl/lwjgl/2.9.1-nightly-20131120/lwjgl-2.9.1-nightly-20131120.jar:/Users/hela/Library/Application Support/minecraft/libraries/org/lwjgl/lwjgl/lwjgl_util/2.9.1-nightly-20131120/lwjgl_util-2.9.1-nightly-20131120.jar:/Users/hela/Library/Application Support/minecraft/libraries/tv/twitch/twitch/5.16/twitch-5.16.jar:/Users/hela/Library/Application Support/minecraft/versions/1.7.4/1.7.4.jar net.minecraft.client.main.Main
[18:11:04 INFO]: Client> Exception in thread "main" java.lang.UnsatisfiedLinkError: /Users/hela/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1393283463447201000/liblwjgl.jnilib: Library not loaded: @rpath/libjawt.dylib Referenced from: /Users/hela/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1393283463447201000/liblwjgl.jnilib Reason: image not found
[18:11:04 INFO]: Client> at java.lang.ClassLoader$NativeLibrary.load(Native Method)
[18:11:04 INFO]: Client> at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1861)
[18:11:04 INFO]: Client> at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1778)
[18:11:04 INFO]: Client> at java.lang.Runtime.loadLibrary0(Runtime.java:823)
[18:11:04 INFO]: Client> at java.lang.System.loadLibrary(System.java:1045)
[18:11:04 INFO]: Client> at org.lwjgl.Sys$1.run(Sys.java:73)
[18:11:04 INFO]: Client> at java.security.AccessController.doPrivileged(Native Method)
[18:11:04 INFO]: Client> at org.lwjgl.Sys.doLoadLibrary(Sys.java:66)
[18:11:04 INFO]: Client> at org.lwjgl.Sys.loadLibrary(Sys.java:95)
[18:11:04 INFO]: Client> at org.lwjgl.Sys.<clinit>(Sys.java:112)
[18:11:04 INFO]: Client> at azi.K(SourceFile:2153)
[18:11:04 INFO]: Client> at net.minecraft.client.main.Main.main(SourceFile:76)
[18:11:06 ERROR]: java.io.IOException: Stream closed
[18:11:06 ERROR]: java.io.IOException: Stream closed
[18:11:06 ERROR]: Game ended with bad state (exit code 1)
[18:11:06 INFO]: Deleting /Users/hela/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1393283463447201000
[18:11:06 INFO]: Ignoring visibility rule and showing launcher due to a game crash