When i try joining it says this

---- Minecraft Crash Report ----
// I just don't know what went wrong

Time: 5/12/13 5:48 PM
Description: Failed to start game

java.lang.IllegalArgumentException: input == null!
at javax.imageio.ImageIO.read(Unknown Source)
at awv.c(SourceFile:98)
at awv.a(SourceFile:92)
at awv.<init>(SourceFile:56)
at net.minecraft.client.Minecraft.a(SourceFile:249)
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:
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– System Details –
Details:
Minecraft Version: 1.5.2
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_17, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 398694888 bytes (380 MB) / 514523136 bytes (490 MB) up to 954466304 bytes (910 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: AMD Radeon HD 7640G GL version 4.2.11476 Compatibility Profile Context, ATI Technologies Inc.
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