ClassiCube

I launch the client and it works just fine, but whenever I try to start a game, the java window closes itself. My debug log looks like this:

Apr 23, 2015 6:20:01 AM net.classicube.launcher.EntryPoint main INFO: ClassiCube Launcher - b64 Apr 23, 2015 6:20:02 AM net.classicube.launcher.UpdateTask doInBackground INFO: Checking for updates. Apr 23, 2015 6:20:05 AM net.classicube.launcher.UpdateTask doInBackground INFO: No updates needed. Apr 23, 2015 6:20:08 AM net.classicube.launcher.gui.UpdateScreen onUpdateDone INFO: onUpdateDone Apr 23, 2015 6:20:08 AM net.classicube.launcher.ClientLauncher launchClient INFO: launchClient Apr 23, 2015 6:20:08 AM net.classicube.launcher.ClientLauncher launchClient INFO: C:\Program Files\Java\jre1.8.0_45\bin\java -cp client.jar;libs/* -Djava.library.path=C:\Users\Pc\AppData\Roaming.net.classicube.client\natives -Dorg.lwjgl.util.Debug=true -Dsun.java2d.noddraw=true -Dsun.awt.noerasebackground=true -Dsun.java2d.d3d=false -Dsun.java2d.opengl=false -Dsun.java2d.pmoffscreen=false -Xmx800m com.oyasunadev.mcraft.client.core.ClassiCubeStandalone none 0 none none http://www.classicube.net/skins/ false 06:20:12 [INFO] Log starts on 2015-04-23 06:20:12 [INFO] LWJGL version: 2.9.1 06:20:12 [INFO] Downloading music and sounds... 06:20:12 [INFO] Done downloading music and sounds! (client closed)

Edit: I forgot to mention that it rarely works. Debug from one of those times:

Apr 23, 2015 6:57:03 AM net.classicube.launcher.EntryPoint main INFO: ClassiCube Launcher - b64 Apr 23, 2015 6:57:04 AM net.classicube.launcher.UpdateTask doInBackground INFO: Checking for updates. Apr 23, 2015 6:57:06 AM net.classicube.launcher.UpdateTask doInBackground INFO: No updates needed. Apr 23, 2015 6:57:09 AM net.classicube.launcher.gui.UpdateScreen onUpdateDone INFO: onUpdateDone Apr 23, 2015 6:57:09 AM net.classicube.launcher.ClientLauncher launchClient INFO: launchClient Apr 23, 2015 6:57:09 AM net.classicube.launcher.ClientLauncher launchClient INFO: C:\Program Files\Java\jre1.8.0_45\bin\java -cp client.jar;libs/* -Djava.library.path=C:\Users\Pc\AppData\Roaming.net.classicube.client\natives -Dorg.lwjgl.util.Debug=true -Dsun.java2d.noddraw=true -Dsun.awt.noerasebackground=true -Dsun.java2d.d3d=false -Dsun.java2d.opengl=false -Dsun.java2d.pmoffscreen=false -Xmx800m com.oyasunadev.mcraft.client.core.ClassiCubeStandalone none 0 none none http://www.classicube.net/skins/ false 06:57:12 [INFO] Log starts on 2015-04-23 06:57:12 [INFO] LWJGL version: 2.9.1 06:57:12 [INFO] Downloading music and sounds... 06:57:12 [INFO] Done downloading music and sounds! 06:57:15 [INFO] GPU Vendor: NVIDIA Corporation | Renderer: GeForce 6150SE nForce 430/integrated/SSE2 | OpenGL version: 2.1.2 06:57:15 [INFO] Loading level C:\Users\Pc\AppData\Roaming.net.classicube.client\levelc.cw