When i wanna drop a full stack of items (i tested with cobblestone melons cooked beef, so i guess it's with every item) the game crashes

information you guys need :
---- Minecraft Crash Report ----
// Who set us up the TNT?

Time: 14/12/12 13:01
Description: Ticking memory connection

java.lang.NullPointerException
at qx.f(SourceFile:451)
at iv.a(SourceFile:297)
at ei.a(SourceFile:46)
at cf.b(SourceFile:55)
at iv.d(SourceFile:57)
at iw.b(SourceFile:39)
at bec.b(SourceFile:84)
at net.minecraft.server.MinecraftServer.r(SourceFile:762)
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)

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

– System Details –
Details:
Minecraft Version: 12w50a
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 305629136 bytes (291 MB) / 514523136 bytes (490 MB) up to 954466304 bytes (910 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 5931 (332136 bytes; 0 MB) allocated, 5474 (306544 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
Profiler Position: N/A (disabled)
Vec3 Pool Size: 1299 (72744 bytes; 0 MB) allocated, 1172 (65632 bytes; 0 MB) used
Player Count: 1 / 8; [iq['ToonW'/160, l='Survival_3', x=-68,52, y=58,00, z=66,49]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.