Hopper: java.lang.NullPointerException: Unexpected error

java.lang.NullPointerException: Unexpected error
	at biv.a(SourceFile:481)
	at hd.a(SourceFile:47)
	at hd.a(SourceFile:12)
	at ef.a(SourceFile:164)
	at biy.e(SourceFile:212)

---- Minecraft Crash Report ----
// Who set us up the TNT?

Time: 25.10.13 16:48
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
	at biv.a(SourceFile:481)
	at hd.a(SourceFile:47)
	at hd.a(SourceFile:12)
	at ef.a(SourceFile:164)
	at biy.e(SourceFile:212)
	at azd.o(SourceFile:1281)
	at azd.ad(SourceFile:753)
	at azd.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 biv.a(SourceFile:481)
	at hd.a(SourceFile:47)
	at hd.a(SourceFile:12)
	at ef.a(SourceFile:164)
	at biy.e(SourceFile:212)

-- Affected level --
Details:
	Level name: MpServer
	All players: 2 total; [bje['pilzkopf1510'/629, l='MpServer', x=-39,90, y=35,76, z=1675,50], bld['Kiwistuff'/39, l='MpServer', x=-40,50, y=35,09, z=1674,50]]
	Chunk stats: MultiplayerChunkCache: 286, 286
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-4,33,1677), Chunk: (at 12,2,13 in -1,104; contains blocks -16,0,1664 to -1,255,1679), Region: (-1,3; contains chunks -32,96 to -1,127, blocks -512,0,1536 to -1,255,2047)
	Level time: 4576717 game time, 4841019 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: survival (ID 0). Hardcore: false. Cheats: false
	Forced entities: 68 total; [wl['Creeper'/1375, l='MpServer', x=-106,06, y=4,00, z=1684,59], bje['pilzkopf1510'/629, l='MpServer', x=-22,70, y=5,62, z=1677,45], rn['Painting'/2, l='MpServer', x=-98,50, y=97,50, z=1620,94], us['Chicken'/3, l='MpServer', x=-94,38, y=4,00, z=1600,59], va['Pig'/4, l='MpServer', x=-94,16, y=4,00, z=1713,88], us['Chicken'/5, l='MpServer', x=-66,63, y=4,00, z=1621,38], vw['item.item.egg'/6, l='MpServer', x=-65,81, y=4,13, z=1619,22], bld['Kiwistuff'/39, l='MpServer', x=-29,26, y=34,01, z=1680,35], xc['Zombie'/1367, l='MpServer', x=-43,50, y=4,00, z=1749,50], wx['Skeleton'/1365, l='MpServer', x=-40,50, y=4,00, z=1742,50], xc['Zombie'/287, l='MpServer', x=-24,88, y=4,00, z=1705,88], uq['Bat'/827, l='MpServer', x=-5,59, y=4,70, z=1620,53], uq['Bat'/14, l='MpServer', x=2,35, y=16,49, z=1654,38], xc['Zombie'/285, l='MpServer', x=-16,72, y=4,00, z=1694,88], va['Pig'/18, l='MpServer', x=-33,48, y=4,00, z=1703,42], uq['Bat'/21, l='MpServer', x=32,63, y=15,32, z=1670,21], va['Pig'/22, l='MpServer', x=-5,03, y=4,00, z=1695,91], xc['Zombie'/1348, l='MpServer', x=-24,72, y=4,00, z=1736,72], xc['Zombie'/1346, l='MpServer', x=-32,50, y=4,00, z=1741,50], uq['Bat'/29, l='MpServer', x=3,05, y=12,81, z=1673,59], va['Pig'/30, l='MpServer', x=7,28, y=4,00, z=1672,16], wl['Creeper'/1611, l='MpServer', x=31,50, y=4,00, z=1644,50], xc['Zombie'/1603, l='MpServer', x=19,50, y=4,00, z=1644,50], wx['Skeleton'/291, l='MpServer', x=-79,50, y=4,00, z=1734,50], wl['Creeper'/1376, l='MpServer', x=-100,50, y=4,00, z=1682,50], wy['Slime'/537, l='MpServer', x=-31,40, y=4,00, z=1702,40], bld['Kiwistuff'/39, l='MpServer', x=-25,34, y=4,00, z=1680,56], uq['Bat'/895, l='MpServer', x=31,41, y=17,14, z=1752,50], rn['Painting'/2, l='MpServer', x=-98,50, y=97,50, z=1620,94], uq['Bat'/1550, l='MpServer', x=-44,46, y=4,56, z=1732,80], uq['Bat'/1551, l='MpServer', x=-41,35, y=5,78, z=1718,47], wx['Skeleton'/1341, l='MpServer', x=-75,50, y=4,00, z=1734,50], uq['Bat'/1547, l='MpServer', x=37,58, y=5,79, z=1703,03], wl['Creeper'/1342, l='MpServer', x=-77,50, y=4,00, z=1732,50], xc['Zombie'/1058, l='MpServer', x=-73,50, y=4,00, z=1735,50], uq['Bat'/1536, l='MpServer', x=34,14, y=11,87, z=1710,81], uq['Bat'/1538, l='MpServer', x=25,71, y=5,40, z=1707,61], xc['Zombie'/590, l='MpServer', x=-63,50, y=4,00, z=1753,50], uq['Bat'/1539, l='MpServer', x=18,73, y=8,43, z=1707,13], xc['Zombie'/1326, l='MpServer', x=-46,50, y=4,00, z=1720,50], wx['Skeleton'/598, l='MpServer', x=-20,78, y=4,00, z=1639,59], uq['Bat'/1557, l='MpServer', x=-91,15, y=9,50, z=1750,57], uq['Bat'/1553, l='MpServer', x=-12,43, y=4,01, z=1730,02], bje['pilzkopf1510'/629, l='MpServer', x=-39,90, y=35,76, z=1675,50], uq['Bat'/1554, l='MpServer', x=-8,00, y=8,09, z=1715,58], uq['Bat'/958, l='MpServer', x=11,16, y=7,39, z=1608,97], uq['Bat'/947, l='MpServer', x=19,84, y=5,10, z=1609,63], wl['Creeper'/1475, l='MpServer', x=-25,16, y=4,00, z=1724,91], wl['Creeper'/1473, l='MpServer', x=-25,50, y=4,00, z=1729,50], wl['Creeper'/1472, l='MpServer', x=-23,66, y=4,00, z=1728,56], wl['Creeper'/1487, l='MpServer', x=-117,50, y=4,00, z=1709,50], bld['Kiwistuff'/39, l='MpServer', x=-38,91, y=36,97, z=1676,59], wl['Creeper'/1278, l='MpServer', x=5,50, y=4,00, z=1641,50], bje['pilzkopf1510'/629, l='MpServer', x=-27,70, y=5,62, z=1680,41], rn['Painting'/2, l='MpServer', x=-98,50, y=97,50, z=1620,94], wm['Enderman'/1165, l='MpServer', x=14,34, y=4,00, z=1732,94], wx['Skeleton'/1171, l='MpServer', x=10,50, y=4,00, z=1735,50], wl['Creeper'/767, l='MpServer', x=-11,50, y=4,00, z=1599,50], wx['Skeleton'/1174, l='MpServer', x=10,50, y=4,00, z=1729,50], wz['Spider'/239, l='MpServer', x=2,91, y=4,00, z=1738,91], rn['Painting'/2, l='MpServer', x=-98,50, y=97,50, z=1620,94], xc['Zombie'/1676, l='MpServer', x=-19,50, y=4,00, z=1754,50], wx['Skeleton'/1692, l='MpServer', x=-114,58, y=4,00, z=1690,47], wl['Creeper'/1451, l='MpServer', x=-71,34, y=4,00, z=1749,06], bld['Kiwistuff'/39, l='MpServer', x=-40,50, y=35,09, z=1674,50], wx['Skeleton'/242, l='MpServer', x=3,50, y=4,00, z=1734,50], wl['Creeper'/1452, l='MpServer', x=-70,50, y=4,00, z=1741,50], wl['Creeper'/1455, l='MpServer', x=-72,50, y=4,00, z=1738,50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Non-integrated multiplayer server
Stacktrace:
	at biz.a(SourceFile:284)
	at azd.b(SourceFile:1951)
	at azd.e(SourceFile:718)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 1.7.2
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_45, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 21818128 bytes (20 MB) / 91136000 bytes (86 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 755 (42280 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.7.2
	LWJGL: 2.9.0
	OpenGL: AMD Radeon HD 7700 Series GL version 4.2.11733 Compatibility Profile Context, ATI Technologies Inc.
	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: 139 (7784 bytes; 0 MB) allocated, 14 (784 bytes; 0 MB) used
	Anisotropic Filtering: Off (1)