Sorry my bad spelling, I do not know much English.
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The bug started when I saw that typing /give Gerottinho 95 (locked chest) crash the game. (On 13w02a.)
After that, I can not create maps. Appears Out of memory or crash.
I thought that only happened in 13w02, and then went back to 1.4.6.
Only now something very strange happened.
When I tried to create the map, after a while, appeared Out of memory, and the screen went white increasing very fast and i closed the game very fast.
I know it could also be the popular "Not Responding" of Windows 7, but was totally white.

About files of the crash, they were not saved in the folder .Minecraft (bug?)

-----Update------

New attachment, which I found on Minecraft.
It's about the "Out of memory".