NullPointerException while launching Game

Hello,

when im trying to launch Minecraft, i`m getting this error in the console:

Launching in C:\Users\Jan\AppData\Roaming\.minecraft
Fatal error launching game. Report this to http://mojang.atlassian.net please!
java.lang.NullPointerException
at net.minecraft.launcher.GameLauncher.getMinecraftArguments(GameLauncher.java:300)
at net.minecraft.launcher.GameLauncher.launchGame(GameLauncher.java:235)
at net.minecraft.launcher.GameLauncher.onDownloadJobFinished(GameLauncher.java:497)
at net.minecraft.launcher.updater.download.DownloadJob.startDownloading(DownloadJob.java:75)
at net.minecraft.launcher.Launcher$1.run(Launcher.java:157)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)