Hopper: java.lang.SecurityException: SHA1 digest error for avg.class

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-24338/

Crash:

java.lang.SecurityException: SHA1 digest error for avg.class
	at sun.security.util.ManifestEntryVerifier.verify(ManifestEntryVerifier.java:210)
	at java.util.jar.JarVerifier.processEntry(JarVerifier.java:218)
	at java.util.jar.JarVerifier.update(JarVerifier.java:205)
	at java.util.jar.JarVerifier$VerifierStream.read(JarVerifier.java:426)
	at sun.misc.Resource.getBytes(Resource.java:124)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:273)
	at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
	at ats.O(SourceFile:386)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// Daisy, daisy...

Time: 13.08.13 14:50
Description: Initializing game

java.lang.SecurityException: SHA1 digest error for avg.class
	at sun.security.util.ManifestEntryVerifier.verify(ManifestEntryVerifier.java:210)
	at java.util.jar.JarVerifier.processEntry(JarVerifier.java:218)
	at java.util.jar.JarVerifier.update(JarVerifier.java:205)
	at java.util.jar.JarVerifier$VerifierStream.read(JarVerifier.java:426)
	at sun.misc.Resource.getBytes(Resource.java:124)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:273)
	at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
	at ats.O(SourceFile:386)
	at ats.d(SourceFile:599)
	at net.minecraft.client.main.Main.main(SourceFile:101)


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

-- Head --
Stacktrace:
	at sun.security.util.ManifestEntryVerifier.verify(ManifestEntryVerifier.java:210)
	at java.util.jar.JarVerifier.processEntry(JarVerifier.java:218)
	at java.util.jar.JarVerifier.update(JarVerifier.java:205)
	at java.util.jar.JarVerifier$VerifierStream.read(JarVerifier.java:426)
	at sun.misc.Resource.getBytes(Resource.java:124)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:273)
	at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
	at ats.O(SourceFile:386)

-- Initialization --
Details:
Stacktrace:
	at ats.d(SourceFile:599)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Linux (amd64) version 3.2.0-4-amd64
	Java Version: 1.6.0_27, Sun Microsystems Inc.
	Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Sun Microsystems Inc.
	Memory: 68061176 bytes (64 MB) / 132382720 bytes (126 MB) up to 954466304 bytes (910 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
	Launched Version: 1.6.2Mods
	LWJGL: 2.9.0
	OpenGL: ATI Radeon HD 5450 GL version 4.2.11762 Compatibility Profile Context, ATI Technologies Inc.
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Sphax PureBDcraft  64x MC16.zip
	Current Language: English (UK)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-24338/2588349/