Hopper: java.lang.NoClassDefFoundError: atm

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-9653/

Crash:

java.lang.NoClassDefFoundError: atm
	at bfb.i(SourceFile:1229)
	at bfb.a(SourceFile:784)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// On the bright side, I bought you a teddy bear!

Time: 13. 9. 6 오후 9:25
Description: Unexpected error

java.lang.NoClassDefFoundError: atm
	at bfb.i(SourceFile:1229)
	at bfb.a(SourceFile:784)
	at bfb.b(SourceFile:695)
	at ats.S(SourceFile:686)
	at ats.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)
Caused by: java.lang.ClassNotFoundException: atm
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 6 more


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at bfb.i(SourceFile:1229)
	at bfb.a(SourceFile:784)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdf['lgs0321'/316, l='MpServer', x=8.50, y=66.62, z=8.50]]
	Chunk stats: MultiplayerChunkCache: 0
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (0,64,0), Chunk: (at 0,4,0 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 93216 game time, 131120 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 1 total; [bdf['lgs0321'/316, l='MpServer', x=8.50, y=66.62, z=8.50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bda.a(SourceFile:284)
	at ats.b(SourceFile:1761)
	at ats.d(SourceFile:633)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 108262296 bytes (103 MB) / 189001728 bytes (180 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 10819 (605864 bytes; 0 MB) allocated, 10819 (605864 bytes; 0 MB) used
	Suspicious classes: ~~ERROR~~ NoClassDefFoundError: org/bouncycastle/jcajce/provider/digest/MD2$Digest
	IntCache: cache: 1, tcache: 0, allocated: 1, tallocated: 63
	Launched Version: 1.6.2
	LWJGL: 2.9.0
	OpenGL: GeForce GT 620/PCIe/SSE2 GL version 4.3.0, NVIDIA Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Current Language: 한국어 (KR)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 16 (896 bytes; 0 MB) allocated, 16 (896 bytes; 0 MB) used

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-9653/8313107/