(MindCrack) I crash whenever I load a Single PLayer World.

[KoopaFreak600]

Whenever I open a single payer world I get an error and my minecraft crashes/freezes.
If anyone could help me it would be great.

Error Message In Log:
2013-02-03 09:49:52 [SEVERE] [ForgeModLoader] The following problems were captured during this phase
2013-02-03 09:49:52 [INFO] [STDERR] Exception in thread "Server thread" cpw.mods.fml.common.LoaderException
2013-02-03 09:49:52 [INFO] [STDERR] at cpw.mods.fml.common.LoadController.transition(LoadController.java:117)
2013-02-03 09:49:52 [INFO] [STDERR] at cpw.mods.fml.common.Loader.serverStopped(Loader.java:761)
2013-02-03 09:49:52 [INFO] [STDERR] at cpw.mods.fml.common.FMLCommonHandler.handleServerStopped(FMLCommonHandler.java:464)
2013-02-03 09:49:52 [INFO] [STDERR] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:559)
2013-02-03 09:49:52 [INFO] [STDERR] at fy.run(SourceFile:849)