Crashed in a Skyblock server

Put the summary of the bug you're having here

I sent a message and the game crashed when I pressed Enter.

Describe what you thought should happen here

The message would be sent and I could keep farming.

Describe what happened here

The game crashed.

Steps to Reproduce:

It's on a server, but here's the error log:

---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 04/07/13 00:19
Description: Deserializing Message

java.lang.ClassCastException: com.google.gson.JsonPrimitive cannot be cast to com.google.gson.JsonObject
	at cw.a(SourceFile:14)
	at cw.deserialize(SourceFile:10)
	at com.google.gson.TreeTypeAdapter.read(TreeTypeAdapter.java:58)
	at com.google.gson.Gson.fromJson(Gson.java:795)
	at com.google.gson.Gson.fromJson(Gson.java:761)
	at com.google.gson.Gson.fromJson(Gson.java:710)
	at com.google.gson.Gson.fromJson(Gson.java:682)
	at cu.c(SourceFile:220)
	at bcn.a(SourceFile:518)
	at dl.a(SourceFile:49)
	at cn.b(SourceFile:350)
	at bcn.d(SourceFile:95)
	at bcu.b(SourceFile:60)
	at atn.k(SourceFile:1380)
	at atn.S(SourceFile:662)
	at atn.d(SourceFile:618)
	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 cw.a(SourceFile:14)
	at cw.deserialize(SourceFile:10)
	at com.google.gson.TreeTypeAdapter.read(TreeTypeAdapter.java:58)
	at com.google.gson.Gson.fromJson(Gson.java:795)
	at com.google.gson.Gson.fromJson(Gson.java:761)
	at com.google.gson.Gson.fromJson(Gson.java:710)
	at com.google.gson.Gson.fromJson(Gson.java:682)

-- Serialized Message --
Details:
	JSON string: Cannot send chat message.
Stacktrace:
	at cu.c(SourceFile:220)
	at bcn.a(SourceFile:518)
	at dl.a(SourceFile:49)
	at cn.b(SourceFile:350)
	at bcn.d(SourceFile:95)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bcx['Fullzop'/9032471, l='MpServer', x=754,70, y=19,62, z=32846,52]]
	Chunk stats: MultiplayerChunkCache: 81
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (750,20,32846), Chunk: (at 14,1,14 in 46,2052; contains blocks 736,0,32832 to 751,255,32847), Region: (1,64; contains chunks 32,2048 to 63,2079, blocks 512,0,32768 to 1023,255,33279)
	Level time: 24133179 game time, 24133179 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: adventure (ID 2). Hardcore: false. Cheats: false
	Forced entities: 3 total; [ro['Cow'/9229560, l='MpServer', x=745,72, y=24,00, z=32849,53], rn['Chicken'/9229559, l='MpServer', x=744,47, y=24,00, z=32845,81], bcx['Fullzop'/9032471, l='MpServer', x=754,70, y=19,62, z=32846,52]]
	Retry entities: 0 total; []
Stacktrace:
	at bcu.a(SourceFile:284)
	at atn.k(SourceFile:1387)
	at atn.S(SourceFile:662)
	at atn.d(SourceFile:618)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bcx['Fullzop'/9032471, l='MpServer', x=754,70, y=19,62, z=32846,52]]
	Chunk stats: MultiplayerChunkCache: 81
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (750,20,32846), Chunk: (at 14,1,14 in 46,2052; contains blocks 736,0,32832 to 751,255,32847), Region: (1,64; contains chunks 32,2048 to 63,2079, blocks 512,0,32768 to 1023,255,33279)
	Level time: 24133179 game time, 24133179 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: adventure (ID 2). Hardcore: false. Cheats: false
	Forced entities: 3 total; [ro['Cow'/9229560, l='MpServer', x=745,72, y=24,00, z=32849,53], rn['Chicken'/9229559, l='MpServer', x=744,47, y=24,00, z=32845,81], bcx['Fullzop'/9032471, l='MpServer', x=754,70, y=19,62, z=32846,52]]
	Retry entities: 0 total; []

-- System Details --
Details:
	Minecraft Version: 1.6.1
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_21, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 124235344 bytes (118 MB) / 220192768 bytes (209 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 485 (27160 bytes; 0 MB) allocated, 42 (2352 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Launched Version: 1.6.1
	LWJGL: 2.9.0
	OpenGL: Intel(R) Graphics Media Accelerator 3600 Series GL version 3.0, Intel Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 100 (5600 bytes; 0 MB) allocated, 21 (1176 bytes; 0 MB) used

Hope this will help.