Below is the crash report Minecraft generated after it crashed.
---- Minecraft Crash Report ----
// But it works on my machine.

Time: 6/27/14 12:50 AM
Description: Getting biome

java.lang.NullPointerException: Getting biome
at apw.a(SourceFile:934)
at aha.a(SourceFile:115)
at ahq.a(SourceFile:157)
at alv.d(SourceFile:50)
at bny.p(SourceFile:3641)
at bny.b(SourceFile:136)
at boa.a(SourceFile:163)
at bom.a(SourceFile:1282)
at bof.a(SourceFile:958)
at bof.b(SourceFile:814)
at ban.ak(SourceFile:801)
at ban.f(SourceFile:728)
at net.minecraft.client.main.Main.main(SourceFile:148)

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

– Head –
Stacktrace:
at apw.a(SourceFile:934)

– Coordinates of biome request –
Details:
Location: World: (63,0,970), Chunk: (at 15,0,10 in 3,60; contains blocks 48,0,960 to 63,255,975), Region: (0,1; contains chunks 0,32 to 31,63, blocks 0,0,512 to 511,255,1023)
Stacktrace:
at aha.a(SourceFile:115)
at ahq.a(SourceFile:157)
at alv.d(SourceFile:50)
at bny.p(SourceFile:3641)
at bny.b(SourceFile:136)
at boa.a(SourceFile:163)
at bom.a(SourceFile:1282)
at bof.a(SourceFile:958)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [blw['Gwadani_Joe'/257, l='MpServer', x=320.27, y=68.01, z=972.97]]
Chunk stats: MultiplayerChunkCache: 1089, 1089
Level seed: 0
Level generator: ID 02 - largeBiomes, ver 0. Features enabled: false
Level generator options:
Level spawn location: World: (194,64,910), Chunk: (at 2,4,14 in 12,56; contains blocks 192,0,896 to 207,255,911), Region: (0,1; contains chunks 0,32 to 31,63, blocks 0,0,512 to 511,255,1023)
Level time: 6730017 game time, 6742872 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: 90 total; [wd['Bat'/13353, l='MpServer', x=331.75, y=31.10, z=1007.59], yk['Skeleton'/9773, l='MpServer', x=332.50, y=33.00, z=902.50], xy['Creeper'/9774, l='MpServer', x=331.50, y=34.00, z=900.91], xy['Creeper'/9775, l='MpServer', x=329.50, y=33.00, z=902.50], yp['Zombie'/16031, l='MpServer', x=366.50, y=18.00, z=933.50], yp['Zombie'/16030, l='MpServer', x=365.50, y=18.00, z=935.50], blw['Gwadani_Joe'/257, l='MpServer', x=320.27, y=68.01, z=972.97], yp['Zombie'/15756, l='MpServer', x=380.50, y=37.00, z=995.50], wd['Bat'/11695, l='MpServer', x=374.10, y=21.55, z=928.50], xy['Creeper'/15759, l='MpServer', x=392.50, y=39.00, z=916.50], yp['Zombie'/16036, l='MpServer', x=364.50, y=18.00, z=933.50], wd['Bat'/61, l='MpServer', x=244.75, y=43.10, z=895.75], yk['Skeleton'/16043, l='MpServer', x=322.50, y=14.00, z=1007.50], yp['Zombie'/11476, l='MpServer', x=287.50, y=12.00, z=1009.50], yk['Skeleton'/15842, l='MpServer', x=399.50, y=18.00, z=914.50], yp['Zombie'/11475, l='MpServer', x=293.50, y=12.00, z=1006.50], yk['Skeleton'/85, l='MpServer', x=259.50, y=22.00, z=1045.91], wr['Squid'/84, l='MpServer', x=272.91, y=58.31, z=1029.72], wr['Squid'/93, l='MpServer', x=289.78, y=54.75, z=937.50], wr['Squid'/95, l='MpServer', x=278.91, y=59.94, z=945.78], yk['Skeleton'/9599, l='MpServer', x=300.50, y=39.00, z=1016.50], wr['Squid'/98, l='MpServer', x=277.50, y=59.25, z=1024.06], ym['Spider'/111, l='MpServer', x=291.66, y=21.00, z=965.56], wd['Bat'/117, l='MpServer', x=303.66, y=39.10, z=1038.88], wr['Squid'/116, l='MpServer', x=289.81, y=58.34, z=1004.06], xl['entity.MinecartChest.name'/115, l='MpServer', x=301.50, y=33.34, z=1000.47], xl['entity.MinecartChest.name'/114, l='MpServer', x=288.50, y=35.34, z=977.47], ym['Spider'/113, l='MpServer', x=288.66, y=21.00, z=961.47], yk['Skeleton'/112, l='MpServer', x=288.00, y=21.00, z=964.69], yp['Zombie'/127, l='MpServer', x=308.03, y=36.00, z=931.47], yp['Zombie'/126, l='MpServer', x=304.56, y=31.00, z=927.44], yk['Skeleton'/10320, l='MpServer', x=374.50, y=34.00, z=999.50], xl['entity.MinecartChest.name'/129, l='MpServer', x=318.47, y=37.34, z=970.84], yk['Skeleton'/131, l='MpServer', x=317.50, y=34.00, z=985.91], wd['Bat'/130, l='MpServer', x=324.00, y=16.76, z=982.59], xl['entity.MinecartChest.name'/133, l='MpServer', x=317.06, y=38.34, z=995.66], wr['Squid'/132, l='MpServer', x=314.00, y=52.97, z=997.11], xl['entity.MinecartChest.name'/134, l='MpServer', x=304.50, y=32.50, z=994.47], wr['Squid'/152, l='MpServer', x=334.13, y=49.09, z=925.09], xl['entity.MinecartChest.name'/154, l='MpServer', x=330.50, y=43.50, z=930.50], yk['Skeleton'/10318, l='MpServer', x=259.50, y=20.00, z=1047.50], xl['entity.MinecartChest.name'/144, l='MpServer', x=329.50, y=20.34, z=910.50], yk['Skeleton'/10319, l='MpServer', x=373.50, y=34.00, z=997.50], yk['Skeleton'/145, l='MpServer', x=329.50, y=32.00, z=904.50], yk['Skeleton'/10316, l='MpServer', x=251.50, y=20.00, z=1052.50], yp['Zombie'/146, l='MpServer', x=324.88, y=31.00, z=919.59], yk['Skeleton'/10317, l='MpServer', x=248.50, y=20.00, z=1050.50], wd['Bat'/147, l='MpServer', x=334.25, y=21.10, z=914.75], yk['Skeleton'/10315, l='MpServer', x=253.50, y=20.00, z=1050.50], yk['Skeleton'/151, l='MpServer', x=328.91, y=32.00, z=919.47], wr['Squid'/171, l='MpServer', x=349.84, y=51.34, z=927.38], yp['Zombie'/13306, l='MpServer', x=252.50, y=16.00, z=938.50], xy['Creeper'/169, l='MpServer', x=347.00, y=34.00, z=915.53], yo['Witch'/175, l='MpServer', x=350.34, y=26.00, z=993.13], yk['Skeleton'/13037, l='MpServer', x=320.50, y=33.00, z=916.50], yp['Zombie'/13038, l='MpServer', x=318.47, y=33.00, z=912.09], wr['Squid'/173, l='MpServer', x=345.13, y=48.06, z=926.91], yp['Zombie'/13039, l='MpServer', x=318.50, y=33.00, z=915.50], yp['Zombie'/163, l='MpServer', x=337.53, y=38.00, z=899.03], yk['Skeleton'/167, l='MpServer', x=345.09, y=33.00, z=930.50], xl['entity.MinecartChest.name'/165, l='MpServer', x=336.47, y=30.34, z=925.59], wd['Bat'/190, l='MpServer', x=361.25, y=20.10, z=933.75], wd['Bat'/188, l='MpServer', x=364.34, y=20.00, z=923.97], yp['Zombie'/176, l='MpServer', x=342.94, y=17.00, z=1047.66], wr['Squid'/205, l='MpServer', x=351.25, y=52.84, z=1007.84], wr['Squid'/207, l='MpServer', x=362.19, y=47.22, z=1035.13], wr['Squid'/206, l='MpServer', x=352.94, y=50.19, z=1016.97], yk['Skeleton'/202, l='MpServer', x=364.56, y=32.00, z=989.88], xy['Creeper'/196, l='MpServer', x=358.16, y=20.00, z=1003.22], yk['Skeleton'/198, l='MpServer', x=362.91, y=32.00, z=997.97], xy['Creeper'/193, l='MpServer', x=365.50, y=35.00, z=985.50], wd['Bat'/13798, l='MpServer', x=264.59, y=28.45, z=925.45], wd['Bat'/13799, l='MpServer', x=261.89, y=27.49, z=926.48], xl['entity.MinecartChest.name'/222, l='MpServer', x=371.47, y=25.50, z=921.50], wd['Bat'/13802, l='MpServer', x=379.85, y=41.25, z=994.44], wd['Bat'/13800, l='MpServer', x=386.51, y=38.90, z=998.59], yp['Zombie'/210, l='MpServer', x=358.50, y=37.00, z=1046.50], xy['Creeper'/11866, l='MpServer', x=379.50, y=30.00, z=1046.50], wr['Squid'/238, l='MpServer', x=374.25, y=59.06, z=1036.44], xy['Creeper'/11865, l='MpServer', x=381.50, y=30.00, z=1045.50], yp['Zombie'/11864, l='MpServer', x=358.59, y=17.00, z=918.88], yp['Zombie'/235, l='MpServer', x=371.50, y=33.00, z=1017.50], xy['Creeper'/233, l='MpServer', x=369.69, y=34.00, z=1006.69], yk['Skeleton'/229, l='MpServer', x=370.30, y=30.00, z=992.30], xl['entity.MinecartChest.name'/228, l='MpServer', x=374.50, y=38.50, z=984.47], yp['Zombie'/11862, l='MpServer', x=358.97, y=17.00, z=926.50], wf['Chicken'/226, l='MpServer', x=376.41, y=62.43, z=970.53], xy['Creeper'/11861, l='MpServer', x=363.50, y=17.00, z=930.50], xy['Creeper'/11860, l='MpServer', x=361.50, y=17.00, z=930.50], xl['entity.MinecartChest.name'/224, l='MpServer', x=370.50, y=14.50, z=938.47]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at blr.a(SourceFile:289)
at ban.b(SourceFile:1972)
at ban.f(SourceFile:737)
at net.minecraft.client.main.Main.main(SourceFile:148)

– System Details –
Details:
Minecraft Version: 1.7.9
Operating System: Windows 8.1 (x86) version 6.3
Java Version: 1.7.0_60, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 130678328 bytes (124 MB) / 442761216 bytes (422 MB) up to 518979584 bytes (494 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 102
Launched Version: 1.7.9
LWJGL: 2.9.1
OpenGL: AMD Radeon HD 7520G GL version 4.2.12420 Compatibility Profile Context 13.151.0.0, ATI Technologies Inc.
GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

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: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Anisotropic Filtering: Off (1)