My brother and I have tried to login a server called citywars, and nothing seems to be working, it keeps saying this...

Minecraft has crashed!
----------------------

Minecraft has stopped running because it encountered a problem; Unexpected error

A full error report has been saved to C:\Users\Anna\AppData\Roaming\.minecraft\crash-reports\crash-2013-03-18_17.30.58-client.txt - Please include a copy of that file (Not this screen!) if you report this crash to anyone; without it, they will not be able to help fix the crash

— BEGIN ERROR REPORT 38f18561 --------
Full report at:
C:\Users\Anna\AppData\Roaming\.minecraft\crash-reports\crash-2013-03-18_17.30.58-client.txt
Please show that file to Mojang, NOT just this screen!

Generated 3/18/13 5:30 PM

– Head –
Stacktrace:
at alj.a(SourceFile:20)
at bfz.a(SourceFile:7167)
at bfz.a(SourceFile:6759)
at bhc.a(SourceFile:271)
at bhc.b(SourceFile:323)
at awq.a(SourceFile:648)
at awq.a(SourceFile:244)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [bdp['Annais2000'/560687, l='MpServer', x=-0.50, y=72.63, z=-2.50]]
Chunk stats: MultiplayerChunkCache: 0
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (-1,71,-3), Chunk: (at 15,4,13 in -1,-1; contains blocks -16,0,-16 to -1,255,-1), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
Level time: 403071960 game time, 535469936 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: 1 total; [bdp['Annais2000'/560687, l='MpServer', x=-0.50, y=72.63, z=-2.50]]
Retry entities: 0 total; []
Stacktrace:
at bdm.a(SourceFile:282)
at net.minecraft.client.Minecraft.b(SourceFile:1879)
at net.minecraft.client.Minecraft.run(SourceFile:538)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 1.5
Operating System: Windows 8 (x86) version 6.2
Java Version: 1.7.0_17, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 473888952 bytes (451 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 3679 (206024 bytes; 0 MB) allocated, 3679 (206024 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
LWJGL: 2.4.2
OpenGL: Intel(R) HD Graphics GL version 3.1.0 - Build 9.17.10.2828, Intel
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Texture Pack: Default
Profiler Position: N/A (disabled)
Vec3 Pool Size: 32 (1792 bytes; 0 MB) allocated, 32 (1792 bytes; 0 MB) used

java.lang.ArrayIndexOutOfBoundsException: 16
at alj.a(SourceFile:20)
at bfz.a(SourceFile:7167)
at bfz.a(SourceFile:6759)
at bhc.a(SourceFile:271)
at bhc.b(SourceFile:323)
at awq.a(SourceFile:648)
at awq.a(SourceFile:244)
at bfk.b(SourceFile:750)
at net.minecraft.client.Minecraft.K(SourceFile:595)
at net.minecraft.client.Minecraft.run(SourceFile:524)
at java.lang.Thread.run(Unknown Source)
— END ERROR REPORT 1b4196b7 ----------

Im not sure what it is, but we are getting really mad that it keeps doing this. PLEASE HELP US!!!!!!!!!!!!!!!!!!!!!!!