Crash when reaching y=254

When I tried to be over 254 I get a crash, the following crash:

---- Minecraft Crash Report ----
// Quite honestly, I wouldn't worry myself about that.

Time: 18/08/14 16:27
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
	at cki.a(SourceFile:798)
	at cjd.a(SourceFile:1189)
	at cjd.a(SourceFile:1123)
	at cjd.b(SourceFile:976)
	at bsr.as(SourceFile:901)
	at bsr.a(SourceFile:312)
	at net.minecraft.client.main.Main.main(SourceFile:120)


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

-- Head --
Stacktrace:
	at cki.a(SourceFile:798)
	at cjd.a(SourceFile:1189)
	at cjd.a(SourceFile:1123)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [cij['lAngelP'/503, l='MpServer', x=-186,74, y=254,69, z=-171,76]]
	Chunk stats: MultiplayerChunkCache: 450, 450
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: -179,00,64,00,-166,00 - World: (-179,64,-166), Chunk: (at 13,4,10 in -12,-11; contains blocks -192,0,-176 to -177,255,-161), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Level time: 665 game time, 665 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: 78 total; [acn['Squid'/75982, l='MpServer', x=-173,50, y=51,00, z=-111,50], acn['Squid'/75983, l='MpServer', x=-175,50, y=51,00, z=-108,50], acn['Squid'/75980, l='MpServer', x=-170,50, y=62,00, z=-198,50], agb['Spider'/74776, l='MpServer', x=-129,50, y=14,00, z=-212,50], acn['Squid'/75981, l='MpServer', x=-174,50, y=51,00, z=-113,50], acn['Squid'/77473, l='MpServer', x=-126,50, y=47,00, z=-109,50], acn['Squid'/75979, l='MpServer', x=-169,50, y=62,00, z=-201,50], acn['Squid'/75977, l='MpServer', x=-165,50, y=62,00, z=-201,50], acn['Squid'/75972, l='MpServer', x=-164,50, y=62,00, z=-202,50], acn['Squid'/75988, l='MpServer', x=-148,50, y=54,00, z=-201,50], acn['Squid'/75987, l='MpServer', x=-150,50, y=54,00, z=-199,50], acn['Squid'/75986, l='MpServer', x=-149,50, y=54,00, z=-201,50], acn['Squid'/75985, l='MpServer', x=-149,50, y=54,00, z=-198,50], acn['Squid'/75984, l='MpServer', x=-175,50, y=51,00, z=-111,50], acn['Squid'/77453, l='MpServer', x=-169,50, y=61,00, z=-201,50], acn['Squid'/77450, l='MpServer', x=-162,50, y=61,00, z=-199,50], acn['Squid'/77451, l='MpServer', x=-163,50, y=61,00, z=-204,50], acn['Squid'/77449, l='MpServer', x=-163,50, y=61,00, z=-203,50], acn['Squid'/77468, l='MpServer', x=-129,50, y=47,00, z=-108,50], acn['Squid'/77543, l='MpServer', x=-135,50, y=59,00, z=-108,50], aca['Rabbit'/76, l='MpServer', x=-201,73, y=69,19, z=-202,25], abz['Pig'/77, l='MpServer', x=-197,50, y=68,00, z=-205,50], abz['Pig'/78, l='MpServer', x=-207,22, y=68,00, z=-206,94], abz['Pig'/79, l='MpServer', x=-196,91, y=69,00, z=-204,00], abz['Pig'/72, l='MpServer', x=-209,97, y=68,00, z=-195,28], aca['Rabbit'/74, l='MpServer', x=-199,66, y=63,00, z=-209,66], aca['Rabbit'/75, l='MpServer', x=-199,81, y=65,32, z=-206,79], abz['Pig'/81, l='MpServer', x=-202,47, y=69,00, z=-195,88], abz['Pig'/80, l='MpServer', x=-195,50, y=68,00, z=-204,50], abz['Pig'/83, l='MpServer', x=-195,53, y=70,00, z=-189,19], abz['Pig'/82, l='MpServer', x=-200,88, y=68,34, z=-193,88], cij['lAngelP'/503, l='MpServer', x=-186,74, y=254,69, z=-171,76], acn['Squid'/75845, l='MpServer', x=-139,50, y=54,00, z=-175,50], acn['Squid'/75844, l='MpServer', x=-139,50, y=54,00, z=-174,50], acn['Squid'/75843, l='MpServer', x=-136,50, y=54,00, z=-176,50], acn['Squid'/75842, l='MpServer', x=-132,50, y=54,00, z=-180,50], acn['Squid'/75862, l='MpServer', x=-133,50, y=51,00, z=-195,50], acn['Squid'/75863, l='MpServer', x=-135,50, y=51,00, z=-198,50], acn['Squid'/75861, l='MpServer', x=-134,50, y=51,00, z=-197,50], acn['Squid'/77367, l='MpServer', x=-124,50, y=54,00, z=-125,50], acn['Squid'/75864, l='MpServer', x=-133,50, y=51,00, z=-197,50], acn['Squid'/77327, l='MpServer', x=-145,50, y=55,00, z=-189,50], acn['Squid'/77326, l='MpServer', x=-145,50, y=55,00, z=-191,50], acn['Squid'/77325, l='MpServer', x=-143,50, y=55,00, z=-189,50], acn['Squid'/77324, l='MpServer', x=-143,50, y=55,00, z=-187,50], ads['Falling Block'/175, l='MpServer', x=-327,50, y=14,09, z=-205,50], ads['Falling Block'/186, l='MpServer', x=-326,50, y=14,09, z=-202,50], ads['Falling Block'/187, l='MpServer', x=-327,50, y=14,09, z=-202,50], ads['Falling Block'/184, l='MpServer', x=-324,50, y=14,09, z=-204,50], ads['Falling Block'/185, l='MpServer', x=-327,50, y=14,09, z=-203,50], ads['Falling Block'/188, l='MpServer', x=-325,50, y=14,09, z=-202,50], ads['Falling Block'/178, l='MpServer', x=-326,50, y=14,09, z=-204,50], ads['Falling Block'/179, l='MpServer', x=-325,50, y=14,09, z=-204,50], ads['Falling Block'/177, l='MpServer', x=-326,50, y=14,09, z=-205,50], ads['Falling Block'/182, l='MpServer', x=-326,50, y=14,09, z=-203,50], ads['Falling Block'/183, l='MpServer', x=-325,50, y=14,09, z=-203,50], ads['Falling Block'/181, l='MpServer', x=-327,50, y=14,09, z=-204,50], acn['Squid'/77379, l='MpServer', x=-131,50, y=57,00, z=-193,50], acn['Squid'/77378, l='MpServer', x=-131,50, y=57,00, z=-196,50], acn['Squid'/77377, l='MpServer', x=-128,50, y=57,00, z=-196,50], acn['Squid'/77380, l='MpServer', x=-130,50, y=57,00, z=-194,50], ads['Falling Block'/274, l='MpServer', x=-277,50, y=9,09, z=-259,50], ads['Falling Block'/9522, l='MpServer', x=-326,50, y=22,20, z=-203,50], ads['Falling Block'/9521, l='MpServer', x=-324,50, y=21,20, z=-205,50], ads['Falling Block'/9520, l='MpServer', x=-325,50, y=22,20, z=-204,50], ads['Falling Block'/9518, l='MpServer', x=-326,50, y=22,20, z=-205,50], ads['Falling Block'/9519, l='MpServer', x=-326,50, y=22,20, z=-204,50], ads['Falling Block'/9517, l='MpServer', x=-325,50, y=21,20, z=-205,50], acn['Squid'/77277, l='MpServer', x=-126,50, y=55,00, z=-220,50], acn['Squid'/75619, l='MpServer', x=-123,50, y=53,00, z=-170,50], acn['Squid'/77276, l='MpServer', x=-129,50, y=55,00, z=-219,50], acn['Squid'/75618, l='MpServer', x=-123,50, y=53,00, z=-167,50], acn['Squid'/77279, l='MpServer', x=-125,50, y=55,00, z=-216,50], acn['Squid'/77278, l='MpServer', x=-128,50, y=55,00, z=-216,50], acn['Squid'/75744, l='MpServer', x=-133,50, y=59,00, z=-142,50], acn['Squid'/75745, l='MpServer', x=-132,50, y=59,00, z=-145,50], acn['Squid'/75743, l='MpServer', x=-132,50, y=59,00, z=-144,50], acn['Squid'/75742, l='MpServer', x=-134,50, y=59,00, z=-141,50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at cei.a(SourceFile:308)
	at bsr.b(SourceFile:2255)
	at bsr.a(SourceFile:326)
	at net.minecraft.client.main.Main.main(SourceFile:120)

-- System Details --
Details:
	Minecraft Version: 14w34a
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 466760096 bytes (445 MB) / 874512384 bytes (834 MB) up to 3817865216 bytes (3641 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx4G
	IntCache: cache: 1, tcache: 1, allocated: 12, tallocated: 94
	Launched Version: 14w34a
	LWJGL: 2.9.1
	OpenGL: GeForce GTX 770/PCIe/SSE2 GL version 4.4.0, NVIDIA Corporation
	GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

	Using VBOs: Yes
	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)