Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at axz.a(SourceFile:64)
	at axt.a(SourceFile:42)
	at ayw.a(SourceFile:71)
	at ayw.d(SourceFile:139)
	at ayw.m(SourceFile:110)

---- Minecraft Crash Report ----
// Everything's going to plan. No, really, that was supposed to happen.

Time: 09-06-13 02:16 PM
Description: Updating screen events

java.lang.NullPointerException
	at axz.a(SourceFile:64)
	at axt.a(SourceFile:42)
	at ayw.a(SourceFile:71)
	at ayw.d(SourceFile:139)
	at ayw.m(SourceFile:110)
	at awb.m(SourceFile:1202)
	at awb.V(SourceFile:686)
	at awb.e(SourceFile:642)
	at net.minecraft.client.main.Main.main(SourceFile:103)


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

-- Head --
Stacktrace:
	at axz.a(SourceFile:64)
	at axt.a(SourceFile:42)
	at ayw.a(SourceFile:71)
	at ayw.d(SourceFile:139)
	at ayw.m(SourceFile:110)

-- Affected screen --
Details:
	Screen name: bof
Stacktrace:
	at awb.m(SourceFile:1202)
	at awb.V(SourceFile:686)
	at awb.e(SourceFile:642)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w36b
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 299030104 bytes (285 MB) / 517775360 bytes (493 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 209423 (11727688 bytes; 11 MB) allocated, 2 (112 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Launched Version: 13w36b
	LWJGL: 2.9.0
	OpenGL: Intel 945GM GL version 1.4.0 - Build 8.14.10.1930, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: Español (México)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null