Idk what this bug named

Crash after shooting bow(with fire 5) and arrow trough nether portal
Crash report:

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

Minecraft has stopped running because it encountered a problem; Ticking entity

A full error report has been saved to C:\Users\Asus\AppData\Roaming\.minecraft\crash-reports\crash-2012-12-23_18.22.57-server.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 5975d960 --------
Full report at:
C:\Users\Asus\AppData\Roaming\.minecraft\crash-reports\crash-2012-12-23_18.22.57-server.txt
Please show that file to Mojang, NOT just this screen!

Generated 23/12/12 18:23

– Head –
Stacktrace:
at xp.a(SourceFile:59)
at qz.j_(SourceFile:273)
at yc.a(SourceFile:1319)
at in.a(SourceFile:450)
at yc.g(SourceFile:1297)

– Entity being ticked –
Details:
Entity Type: Arrow (qz)
Entity ID: 64744
Name: arrow
Exact location: -1,00, 87,50, 29,00
Block location: World: (-1,87,29), Chunk: (at 15,5,13 in -1,1; contains blocks -16,0,16 to -1,255,31), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Momentum: 0,23, 0,64, 1,67
Stacktrace:
at yc.h(SourceFile:1196)
at in.h(SourceFile:362)

– Affected level –
Details:
Level name: Lan
All players: 1 total; [iq['kevin_aldily'/23434, l='Lan', x=-1,00, y=87,50, z=29,00]]
Chunk stats: ServerChunkCache: 441 Drop: 0
Level seed: 321169029
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (0,0,0), Chunk: (at 0,0,0 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 0 game time, 0 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: ~_ERROR~ NullPointerException: null
Stacktrace:
at net.minecraft.server.MinecraftServer.r(SourceFile:744)
at net.minecraft.server.MinecraftServer.q(SourceFile:679)
at bdz.q(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:613)
at fy.run(SourceFile:849)

– System Details –
Details:
Minecraft Version: 1.4.6
Operating System: Windows 7 (x86) version 6.1
Java Version: 1.7.0_09, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 118426568 bytes (112 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 4166 (233296 bytes; 0 MB) allocated, 4166 (233296 bytes; 0 MB) used
Suspicious classes: ~_ERROR~ NoClassDefFoundError: com/pclewis/mcpatcher/mod/TileOverride$1
IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
Profiler Position: N/A (disabled)
Vec3 Pool Size: 1093 (61208 bytes; 0 MB) allocated, 896 (50176 bytes; 0 MB) used
Player Count: 2 / 8; [iq['angeloanan'/22691, l='Lan', x=-10,30, y=70,00, z=260,25], iq['kevin_aldily'/23434, l='Lan', x=-1,00, y=87,50, z=29,00]]
Type: Integrated Server (map_client.txt)
Is Modded: Very likely; Jar signature invalidated

java.lang.NullPointerException
at xp.a(SourceFile:59)
at qz.j_(SourceFile:273)
at yc.a(SourceFile:1319)
at in.a(SourceFile:450)
at yc.g(SourceFile:1297)
at yc.h(SourceFile:1196)
at in.h(SourceFile:362)
at net.minecraft.server.MinecraftServer.r(SourceFile:744)
at net.minecraft.server.MinecraftServer.q(SourceFile:679)
at bdz.q(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:613)
at fy.run(SourceFile:849)
— END ERROR REPORT 6e50fefe ----------

How to do this:
1. make portal to nether
2. open to lan
3. shoot arrow with bow(fire 5) trough the nether portal
4. enter the portal
5. Crashing

note: i dont have any mods