So, I was messing around with Command Blocks to make a door that opened when ever I shot a bow. It removed the bow and opened the door but crashed on giving me the bow.

The crash report follows:
---- Minecraft Crash Report ----
// Surprise! Haha. Well, this is awkward.

Time: 28/09/13 00:10
Description: Adding item to inventory

java.lang.NullPointerException
at zi.g(SourceFile:151)
at zi.i(SourceFile:171)
at vd.a(SourceFile:234)
at tq.b_(SourceFile:199)
at vf.r(SourceFile:436)
at vf.e(SourceFile:428)
at pb.h(SourceFile:1194)
at vf.h(SourceFile:211)
at kq.i(SourceFile:204)
at kv.a(SourceFile:201)
at gs.a(SourceFile:136)
at eb.b(SourceFile:63)
at kv.e(SourceFile:69)
at ky.b(SourceFile:40)
at box.b(SourceFile:83)
at net.minecraft.server.MinecraftServer.u(SourceFile:494)
at net.minecraft.server.MinecraftServer.t(SourceFile:411)
at bou.t(SourceFile:121)
at net.minecraft.server.MinecraftServer.run(SourceFile:346)
at jc.run(SourceFile:582)

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

– Head –
Stacktrace:
at zi.g(SourceFile:151)
at zi.i(SourceFile:171)

– Item being added –
Details:
Item ID: 0
Item data: 0
Item name: ~_ERROR~ NullPointerException: null
Stacktrace:
at vd.a(SourceFile:234)
at tq.b_(SourceFile:199)
at vf.r(SourceFile:436)
at vf.e(SourceFile:428)
at pb.h(SourceFile:1194)
at vf.h(SourceFile:211)

– Player being ticked –
Details:
Entity Type: null (kq)
Entity ID: 1756193
Entity Name: cybermanme
Entity's Exact location: 996.39, 67.00, 2004.58
Entity's Block location: World: (996,67,2004), Chunk: (at 4,4,4 in 62,125; contains blocks 992,0,2000 to 1007,255,2015), Region: (1,3; contains chunks 32,96 to 63,127, blocks 512,0,1536 to 1023,255,2047)
Entity's Momentum: 0.00, -0.08, 0.00
Stacktrace:
at kq.i(SourceFile:204)
at kv.a(SourceFile:201)
at gs.a(SourceFile:136)
at eb.b(SourceFile:63)
at kv.e(SourceFile:69)

– Ticking connection –
Details:
Connection: kv@74e4582a
Stacktrace:
at ky.b(SourceFile:40)
at box.b(SourceFile:83)
at net.minecraft.server.MinecraftServer.u(SourceFile:494)
at net.minecraft.server.MinecraftServer.t(SourceFile:411)
at bou.t(SourceFile:121)
at net.minecraft.server.MinecraftServer.run(SourceFile:346)
at jc.run(SourceFile:582)

– System Details –
Details:
Minecraft Version: 13w39b
Operating System: Windows 8 (amd64) version 6.2
Java Version: 1.7.0_40, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 16456680 bytes (15 MB) / 282066944 bytes (269 MB) up to 954728448 bytes (910 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
AABB Pool Size: 257 (14392 bytes; 0 MB) allocated, 128 (7168 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Profiler Position: N/A (disabled)
Vec3 Pool Size: 19753 (1106168 bytes; 1 MB) allocated, 4 (224 bytes; 0 MB) used
Player Count: 1 / 8; [kq['cybermanme'/1756193, l='Redstoning!', x=996.39, y=67.00, z=2004.58]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.