Hopper: java.lang.UnsupportedOperationException: Unexpected change in protocol to null

java.lang.UnsupportedOperationException: Unexpected change in protocol to null
	at bjs.a(SourceFile:126)
	at ej.a(SourceFile:167)
	at bjr.a(SourceFile:245)
	at bfz.e(SourceFile:108)

---- Minecraft Crash Report ----
// This doesn't make any sense!

Time: 6/18/14 7:34 PM
Description: Ticking screen

java.lang.UnsupportedOperationException: Unexpected change in protocol to null
	at bjs.a(SourceFile:126)
	at ej.a(SourceFile:167)
	at bjr.a(SourceFile:245)
	at bfz.e(SourceFile:108)
	at bao.p(SourceFile:1343)
	at bao.ak(SourceFile:774)
	at bao.f(SourceFile:728)
	at net.minecraft.client.main.Main.main(SourceFile:148)


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

-- Head --
Stacktrace:
	at bjs.a(SourceFile:126)
	at ej.a(SourceFile:167)
	at bjr.a(SourceFile:245)
	at bfz.e(SourceFile:108)

-- Affected screen --
Details:
	Screen name: bfz
Stacktrace:
	at bao.p(SourceFile:1343)
	at bao.ak(SourceFile:774)
	at bao.f(SourceFile:728)
	at net.minecraft.client.main.Main.main(SourceFile:148)

-- System Details --
Details:
	Minecraft Version: 1.7.10-pre4
	Operating System: Mac OS X (x86_64) version 10.6.8
	Java Version: 1.6.0_65, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 292059352 bytes (278 MB) / 1069416448 bytes (1019 MB) up to 1069416448 bytes (1019 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Launched Version: 1.7.10-pre4
	LWJGL: 2.9.1
	OpenGL: NVIDIA GeForce 7300 GT OpenGL Engine GL version 2.1 NVIDIA-1.6.36, NVIDIA Corporation
	GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because EXT_framebuffer_object is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Anisotropic Filtering: Off (1)