I cannot launch Minecraft. I can login, but upon clicking the 'Play' button, it says: "Coud not find the main class. Program will exit'

It was absolutely fine this morning/afternoon. I still had version 0.7. Then i heard of the new launcher, downoaded 0.9, and now it keeps saying 'Could not find the main class. Program will exit.' and last time it was a texture pack problem, easily fixed, what about this one?

---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 09/06/13 18:47
Description: Rendering screen

java.lang.ArrayIndexOutOfBoundsException: 4096
	at java.awt.image.BufferedImage.getRGB(Unknown Source)
	at bge.a(SourceFile:93)
	at bge.c(SourceFile:332)
	at bjx.a(SourceFile:150)
	at axt.a(SourceFile:175)
	at bjw.a(SourceFile:109)
	at bfq.b(SourceFile:768)
	at net.minecraft.client.Minecraft.K(SourceFile:597)
	at net.minecraft.client.Minecraft.run(SourceFile:526)
	at java.lang.Thread.run(Unknown Source)


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

-- Head --
Stacktrace:
	at java.awt.image.BufferedImage.getRGB(Unknown Source)
	at bge.a(SourceFile:93)
	at bge.c(SourceFile:332)
	at bjx.a(SourceFile:150)
	at axt.a(SourceFile:175)
	at bjw.a(SourceFile:109)

-- Screen render details --
Details:
	Screen name: bjw
	Mouse location: Scaled: (162, 156). Absolute: (324, 166)
	Screen size: Scaled: (427, 240). Absolute: (854, 480). Scale factor of 2
Stacktrace:
	at bfq.b(SourceFile:768)
	at net.minecraft.client.Minecraft.K(SourceFile:597)
	at net.minecraft.client.Minecraft.run(SourceFile:526)
	at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
	Minecraft Version: 1.5.2
	Operating System: Windows XP (x86) version 5.1
	Java Version: 1.6.0_06, Sun Microsystems Inc.
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
	Memory: 12543368 bytes (11 MB) / 55623680 bytes (53 MB) up to 1065484288 bytes (1016 MB)
	JVM Flags: 1 total; -Xmx1G
	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: 2.9.0
	OpenGL: Intel Cantiga GL version 1.5.0 - Build 7.14.10.4953, 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