Minecraft not starting

When I started minecraft it gave me this error every time.

---- Minecraft Crash Report ----
// Quite honestly, I wouldn't worry myself about that.

Time: 8-5-13 15:22
Description: Failed to start game

java.lang.NullPointerException
	at javax.imageio.ImageIO.write(Unknown Source)
	at bio.b(SourceFile:278)
	at bir.b(SourceFile:154)
	at bge.d(SourceFile:351)
	at net.minecraft.client.Minecraft.a(SourceFile:298)
	at avv.a(SourceFile:56)
	at net.minecraft.client.Minecraft.run(SourceFile:507)
	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: 1.5.2
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_17, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 438247344 bytes (417 MB) / 518979584 bytes (494 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -Xms512m -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: Intel(R) HD Graphics 2000 GL version 3.1.0 - Build 9.17.10.2932, Intel
	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

I do not know how to reproduce it nor do I know why this happens and how to fix it.