Crash log:
---- Minecraft Crash Report ----
// Why is it breaking :(

Time: 10/23/13 4:21 PM
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:192)
	at com.google.common.collect.Lists.newArrayList(Lists.java:126)
	at ban.a(SourceFile:144)
	at ban.a(SourceFile:123)
	at ban.a(SourceFile:119)
	at biu.a(SourceFile:456)
	at fz.a(SourceFile:38)
	at fz.a(SourceFile:9)
	at ef.a(SourceFile:143)
	at bix.e(SourceFile:212)
	at azc.o(SourceFile:1281)
	at azc.ad(SourceFile:753)
	at azc.e(SourceFile:704)
	at net.minecraft.client.main.Main.main(SourceFile:103)


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

-- Head --
Stacktrace:
	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:192)
	at com.google.common.collect.Lists.newArrayList(Lists.java:126)
	at ban.a(SourceFile:144)
	at ban.a(SourceFile:123)
	at ban.a(SourceFile:119)
	at biu.a(SourceFile:456)
	at fz.a(SourceFile:38)
	at fz.a(SourceFile:9)
	at ef.a(SourceFile:143)
	at bix.e(SourceFile:212)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bjd['etherock'/4946, l='MpServer', x=-6.70, y=62.62, z=194.23]]
	Chunk stats: MultiplayerChunkCache: 49, 49
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (18,64,248), Chunk: (at 2,4,8 in 1,15; contains blocks 16,0,240 to 31,255,255), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 3799188 game time, 3799188 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: 9 total; [vv['item.tile.sapling.oak'/2869, l='MpServer', x=13.72, y=74.13, z=205.88], bjd['etherock'/4946, l='MpServer', x=-6.70, y=62.62, z=194.23], vv['item.tile.sapling.oak'/2375, l='MpServer', x=5.97, y=68.13, z=201.88], vv['item.item.porkchopCooked'/4945, l='MpServer', x=12.13, y=67.13, z=199.88], up['Bat'/4971, l='MpServer', x=-25.81, y=46.99, z=201.57], up['Bat'/4970, l='MpServer', x=-27.02, y=44.53, z=203.49], vv['item.tile.torch'/4943, l='MpServer', x=7.75, y=73.13, z=196.56], vv['item.tile.sapling.oak'/2514, l='MpServer', x=8.53, y=81.13, z=205.56], vv['item.tile.sapling.oak'/4201, l='MpServer', x=10.09, y=80.13, z=204.00]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Non-integrated multiplayer server
Stacktrace:
	at biy.a(SourceFile:284)
	at azc.b(SourceFile:1949)
	at azc.e(SourceFile:718)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 1.7.1
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_40, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 374623592 bytes (357 MB) / 609222656 bytes (581 MB) up to 954728448 bytes (910 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 7741 (433496 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Launched Version: 1.7.1
	LWJGL: 2.9.0
	OpenGL: GeForce 210/PCIe/SSE2 GL version 3.3.0, NVIDIA Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1943 (108808 bytes; 0 MB) allocated, 20 (1120 bytes; 0 MB) used
	Anisotropic Filtering: On (4)

[16:29:04] [Server thread/INFO]: adam223344 lost connection: TranslatableCompone
nt{key='disconnect.genericReason', args=[Internal Exception: java.io.IOException
: An existing connection was forcibly closed by the remote host], siblings=[], s
tyle=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null,
 obfuscated=null, clickEvent=null, hoverEvent=null}}
[16:29:04] [Server thread/INFO]: adam223344 left the game
[16:29:19] [User Authenticator #3/INFO]: UUID of player adam223344 is 7f5301e567
42427cafe1e0df2fd9f8cb
[16:29:19] [Server thread/INFO]: adam223344[/82.5.77.226:53819] logged in with e
ntity id 661 at (-49.52345296150794, 77.24918707874468, 374.2445096075345)
[16:29:19] [Server thread/INFO]: adam223344 joined the game