Hopper: java.lang.IllegalStateException: Unexpected protocol HANDSHAKING

java.lang.IllegalStateException: Unexpected protocol HANDSHAKING
	at org.apache.commons.lang3.Validate.validState(Validate.java:826)
	at mq.a(SourceFile:32)
	at ef.a(SourceFile:157)

---- Minecraft Crash Report ----
// Shall we play a game?

Time: 10/25/13 3:39 PM
Description: Ticking memory connection

java.lang.IllegalStateException: Unexpected protocol null
	at org.apache.commons.lang3.Validate.validState(Validate.java:826)
	at mq.a(SourceFile:32)
	at ef.a(SourceFile:157)
	at ms.c(SourceFile:134)
	at net.minecraft.server.MinecraftServer.u(SourceFile:529)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at bsk.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at ky.run(SourceFile:617)


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

-- Head --
Stacktrace:
	at org.apache.commons.lang3.Validate.validState(Validate.java:826)
	at mq.a(SourceFile:32)
	at ef.a(SourceFile:157)

-- Ticking connection --
Details:
	Connection: ef@30ed4c2
Stacktrace:
	at ms.c(SourceFile:134)
	at net.minecraft.server.MinecraftServer.u(SourceFile:529)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at bsk.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at ky.run(SourceFile:617)

-- System Details --
Details:
	Minecraft Version: 1.7.2
	Operating System: Mac OS X (x86_64) version 10.6.8
	Java Version: 1.6.0_51, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 204342320 bytes (194 MB) / 504508416 bytes (481 MB) up to 1069416448 bytes (1019 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 1124 (62944 bytes; 0 MB) allocated, 976 (54656 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 137 (7672 bytes; 0 MB) allocated, 131 (7336 bytes; 0 MB) used
	Player Count: 0 / 8; []
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.