Crash with divide by zero ArithmeticException

Hello im new in minecraft when i was building awesome world...suddenly Minecraft crashes then i copy my saved world and reinstall mincraft but it doesnt work and show me this:

---- Minecraft Crash Report ----
// Why is it breaking :(

Time: 1/19/13 6:56 PM
Description: Unexpected error

java.lang.ArithmeticException: / by zero
	at ban.b(SourceFile:741)
	at net.minecraft.client.Minecraft.J(SourceFile:605)
	at net.minecraft.client.Minecraft.run(SourceFile:534)
	at java.lang.Thread.run(Unknown Source)


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

-- System Details --
Details:
	Minecraft Version: 1.4.7
	Operating System: Windows XP (x86) version 5.1
	Java Version: 1.7.0_10, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 3141096 bytes (2 MB) / 42106880 bytes (40 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1024m
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	LWJGL: 2.4.2
	OpenGL: GeForce 6200 TurboCache(TM)/PCI/SSE2/3DNOW! GL version 2.0.0, NVIDIA Corporation
	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: ~~ERROR~~ NullPointerException: null