Minecraft keeps closing when chat on servers

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here
I can keep playing a server

What actually happened was...:
Describe what happened here
Minecraft quits unexpetiviely when I chat on the server

---- Minecraft Crash Report ----
// My bad.

Time: 7/3/13 9:02 PM
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: 4 total; [bcx['Enderman95'/8219873, l='MpServer', x=-0.00, y=147.62, z=10.74], ben['jono_007'/8158713, l='MpServer', x=1.59, y=146.00, z=14.48], ben['kubik1712'/8085657, l='MpServer', x=0.00, y=146.00, z=6.00], ben['DiamondHydra524'/8120115, l='MpServer', x=-0.38, y=146.01, z=13.50]]
	Chunk stats: MultiplayerChunkCache: 225
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (0,146,6), Chunk: (at 0,9,6 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 57962020 game time, 68440417213 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: 16 total; [bcx['Enderman95'/8219873, l='MpServer', x=-0.00, y=147.62, z=10.74], oa['entity.ItemFrame.name'/1, l='MpServer', x=-0.50, y=150.50, z=-4.94], oa['entity.ItemFrame.name'/2, l='MpServer', x=-10.94, y=150.50, z=7.50], ben['DiamondHydra524'/8120115, l='MpServer', x=-0.38, y=146.01, z=13.50], ben['jono_007'/8158713, l='MpServer', x=1.59, y=146.00, z=14.48], oa['entity.ItemFrame.name'/3, l='MpServer', x=-10.94, y=150.50, z=5.50], oa['entity.ItemFrame.name'/4, l='MpServer', x=-0.50, y=150.50, z=17.94], oa['entity.ItemFrame.name'/5, l='MpServer', x=1.50, y=150.50, z=-4.94], oa['entity.ItemFrame.name'/6, l='MpServer', x=7.50, y=147.50, z=-1.94], ben['kubik1712'/8085657, l='MpServer', x=0.00, y=146.00, z=6.00], oa['entity.ItemFrame.name'/7, l='MpServer', x=9.50, y=149.50, z=15.94], oa['entity.ItemFrame.name'/8, l='MpServer', x=7.50, y=149.50, z=15.94], oa['entity.ItemFrame.name'/9, l='MpServer', x=1.50, y=150.50, z=17.94], ben['DiamondHydra524'/8120115, l='MpServer', x=-0.38, y=146.01, z=13.50], ben['jono_007'/8158713, l='MpServer', x=1.59, y=146.00, z=14.48], ben['kubik1712'/8085657, l='MpServer', x=0.00, y=146.00, z=6.00]]
	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: 4 total; [bcx['Enderman95'/8219873, l='MpServer', x=-0.00, y=147.62, z=10.74], ben['jono_007'/8158713, l='MpServer', x=1.59, y=146.00, z=14.48], ben['kubik1712'/8085657, l='MpServer', x=0.00, y=146.00, z=6.00], ben['DiamondHydra524'/8120115, l='MpServer', x=-0.38, y=146.01, z=13.50]]
	Chunk stats: MultiplayerChunkCache: 225
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (0,146,6), Chunk: (at 0,9,6 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 57962020 game time, 68440417213 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: 16 total; [bcx['Enderman95'/8219873, l='MpServer', x=-0.00, y=147.62, z=10.74], oa['entity.ItemFrame.name'/1, l='MpServer', x=-0.50, y=150.50, z=-4.94], oa['entity.ItemFrame.name'/2, l='MpServer', x=-10.94, y=150.50, z=7.50], ben['DiamondHydra524'/8120115, l='MpServer', x=-0.38, y=146.01, z=13.50], ben['jono_007'/8158713, l='MpServer', x=1.59, y=146.00, z=14.48], oa['entity.ItemFrame.name'/3, l='MpServer', x=-10.94, y=150.50, z=5.50], oa['entity.ItemFrame.name'/4, l='MpServer', x=-0.50, y=150.50, z=17.94], oa['entity.ItemFrame.name'/5, l='MpServer', x=1.50, y=150.50, z=-4.94], oa['entity.ItemFrame.name'/6, l='MpServer', x=7.50, y=147.50, z=-1.94], ben['kubik1712'/8085657, l='MpServer', x=0.00, y=146.00, z=6.00], oa['entity.ItemFrame.name'/7, l='MpServer', x=9.50, y=149.50, z=15.94], oa['entity.ItemFrame.name'/8, l='MpServer', x=7.50, y=149.50, z=15.94], oa['entity.ItemFrame.name'/9, l='MpServer', x=1.50, y=150.50, z=17.94], ben['DiamondHydra524'/8120115, l='MpServer', x=-0.38, y=146.01, z=13.50], ben['jono_007'/8158713, l='MpServer', x=1.59, y=146.00, z=14.48], ben['kubik1712'/8085657, l='MpServer', x=0.00, y=146.00, z=6.00]]
	Retry entities: 0 total; []

-- System Details --
Details:
	Minecraft Version: 1.6.1
	Operating System: Mac OS X (x86_64) version 10.8.4
	Java Version: 1.6.0_45, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 44932152 bytes (42 MB) / 116199424 bytes (110 MB) up to 1065025536 bytes (1015 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 158991 (8903496 bytes; 8 MB) allocated, 27 (1512 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 HD Graphics 3000 OpenGL Engine GL version 2.1 INTEL-8.12.47, Intel Inc.
	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: 210 (11760 bytes; 0 MB) allocated, 19 (1064 bytes; 0 MB) used