Minecraft has crashed! (Вопрос внутри)

При запуске Майнкрафт запускается нормально, а при попытке создать мир или подключится к чьей-то игре выдает вот это.
Что это за хрень и как она исправляется знает кто-нибудь?

Minecraft has crashed!
----------------------

Minecraft has stopped running because it encountered a problem; Unexpected error
We were unable to save this report to a file.

--- BEGIN ERROR REPORT 9e426084 --------
Generated 25.12.12 1:31

- Minecraft Version: 1.4.2
- Operating System: Windows 7 (x86) version 6.1
- Java Version: 1.7.0_10, Oracle Corporation
- Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
- Memory: 461051672 bytes (439 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB)
- JVM Flags: 2 total; -Xms512m -Xmx1024m
- AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
- FML: MCP v7.19 FML v4.2.6.422 Minecraft Forge 6.0.1.339 Optifine OptiFine_1.4.2_HD_U_A7 7 mods loaded, 7 mods active
mcp [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
FML [Forge Mod Loader] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
Forge [Minecraft Forge] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
mod_CodeChickenCore [CodeChicken Core] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
mod_NotEnoughItems [Not Enough Items] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
mod_RMBTweak [RMB Tweak] ([1.4.2] RMB Tweak v1.2.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
mod_InvTweaks [Inventory Tweaks] (InvTweaks-1.44-1.4.2.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
- LWJGL: 2.8.4
- OpenGL: GeForce 9600 GT/PCI/SSE2 GL version 2.1.2, NVIDIA Corporation
- Is Modded: Definitely; 'forge,fml'
- Type: Client
- Texture Pack: faithful32pack.zip
- Profiler Position: N/A (disabled)
- Vec3 Pool Size: ~ERROR~ NullPointerException: null

java.lang.RuntimeException: Failed to check session lock, aborting
at agt.h(SaveHandler.java:72)
at agt.(SaveHandler.java:47)
at agp.(AnvilSaveHandler.java:9)
at agq.a(SourceFile:78)
at net.minecraft.client.Minecraft.a(Minecraft.java:1878)
at aru.a(GuiCreateWorld.java:273)
at asw.a(SourceFile:64)
at aru.a(GuiCreateWorld.java:429)
at asw.d(SourceFile:112)
at asw.m(SourceFile:100)
at net.minecraft.client.Minecraft.l(Minecraft.java:1502)
at net.minecraft.client.Minecraft.J(Minecraft.java:854)
at net.minecraft.client.Minecraft.run(Minecraft.java:779)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT 404245ab ----------