Yarrg! I keep having errors when i start playing a world or when i join a server!

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 7/7/13 7:42 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: 1 total; [bcx['Creeper78123'/3925714, l='MpServer', x=-3590.59, y=19.62, z=-4139.76]]
Chunk stats: MultiplayerChunkCache: 441
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (-3590,60,-4136), Chunk: (at 10,3,8 in -225,-259; contains blocks -3600,0,-4144 to -3585,255,-4129), Region: (-8,-9; contains chunks -256,-288 to -225,-257, blocks -4096,0,-4608 to -3585,255,-4097)
Level time: 62719013 game time, 63543678 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: survival (ID 0). Hardcore: false. Cheats: false
Forced entities: 21 total; [rt['Mooshroom'/3925730, l='MpServer', x=-3615.81, y=63.00, z=-4178.66], bcx['Creeper78123'/3925714, l='MpServer', x=-3590.59, y=19.62, z=-4139.76], rt['Mooshroom'/3925731, l='MpServer', x=-3614.13, y=63.00, z=-4178.69], rt['Mooshroom'/3925728, l='MpServer', x=-3612.78, y=63.00, z=-4180.09], rt['Mooshroom'/3925729, l='MpServer', x=-3615.53, y=63.00, z=-4180.72], rt['Mooshroom'/3925732, l='MpServer', x=-3632.81, y=63.00, z=-4172.56], rt['Mooshroom'/3925739, l='MpServer', x=-3635.28, y=63.00, z=-4093.28], rl['Bat'/3927353, l='MpServer', x=-3565.00, y=11.00, z=-4163.35], oa['entity.ItemFrame.name'/3925715, l='MpServer', x=-3589.50, y=62.50, z=-4133.06], to['Skeleton'/3925717, l='MpServer', x=-3627.50, y=25.00, z=-4127.50], rt['Mooshroom'/3925716, l='MpServer', x=-3603.28, y=65.00, z=-4163.69], rt['Mooshroom'/3925719, l='MpServer', x=-3618.94, y=63.00, z=-4109.03], rt['Mooshroom'/3925718, l='MpServer', x=-3628.25, y=63.00, z=-4101.88], rt['Mooshroom'/3925721, l='MpServer', x=-3625.13, y=64.00, z=-4103.84], rt['Mooshroom'/3925720, l='MpServer', x=-3622.56, y=63.00, z=-4104.47], rt['Mooshroom'/3925723, l='MpServer', x=-3616.47, y=64.00, z=-4110.38], rt['Mooshroom'/3925722, l='MpServer', x=-3619.69, y=65.00, z=-4107.66], tc['Creeper'/3925725, l='MpServer', x=-3561.50, y=28.00, z=-4166.50], rt['Mooshroom'/3925724, l='MpServer', x=-3625.41, y=63.00, z=-4168.09], rt['Mooshroom'/3925727, l='MpServer', x=-3601.50, y=71.00, z=-4093.47], to['Skeleton'/3925726, l='MpServer', x=-3549.50, y=23.00, z=-4142.50]]
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['Creeper78123'/3925714, l='MpServer', x=-3590.59, y=19.62, z=-4139.76]]
Chunk stats: MultiplayerChunkCache: 441
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (-3590,60,-4136), Chunk: (at 10,3,8 in -225,-259; contains blocks -3600,0,-4144 to -3585,255,-4129), Region: (-8,-9; contains chunks -256,-288 to -225,-257, blocks -4096,0,-4608 to -3585,255,-4097)
Level time: 62719013 game time, 63543678 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: survival (ID 0). Hardcore: false. Cheats: false
Forced entities: 21 total; [rt['Mooshroom'/3925730, l='MpServer', x=-3615.81, y=63.00, z=-4178.66], bcx['Creeper78123'/3925714, l='MpServer', x=-3590.59, y=19.62, z=-4139.76], rt['Mooshroom'/3925731, l='MpServer', x=-3614.13, y=63.00, z=-4178.69], rt['Mooshroom'/3925728, l='MpServer', x=-3612.78, y=63.00, z=-4180.09], rt['Mooshroom'/3925729, l='MpServer', x=-3615.53, y=63.00, z=-4180.72], rt['Mooshroom'/3925732, l='MpServer', x=-3632.81, y=63.00, z=-4172.56], rt['Mooshroom'/3925739, l='MpServer', x=-3635.28, y=63.00, z=-4093.28], rl['Bat'/3927353, l='MpServer', x=-3565.00, y=11.00, z=-4163.35], oa['entity.ItemFrame.name'/3925715, l='MpServer', x=-3589.50, y=62.50, z=-4133.06], to['Skeleton'/3925717, l='MpServer', x=-3627.50, y=25.00, z=-4127.50], rt['Mooshroom'/3925716, l='MpServer', x=-3603.28, y=65.00, z=-4163.69], rt['Mooshroom'/3925719, l='MpServer', x=-3618.94, y=63.00, z=-4109.03], rt['Mooshroom'/3925718, l='MpServer', x=-3628.25, y=63.00, z=-4101.88], rt['Mooshroom'/3925721, l='MpServer', x=-3625.13, y=64.00, z=-4103.84], rt['Mooshroom'/3925720, l='MpServer', x=-3622.56, y=63.00, z=-4104.47], rt['Mooshroom'/3925723, l='MpServer', x=-3616.47, y=64.00, z=-4110.38], rt['Mooshroom'/3925722, l='MpServer', x=-3619.69, y=65.00, z=-4107.66], tc['Creeper'/3925725, l='MpServer', x=-3561.50, y=28.00, z=-4166.50], rt['Mooshroom'/3925724, l='MpServer', x=-3625.41, y=63.00, z=-4168.09], rt['Mooshroom'/3925727, l='MpServer', x=-3601.50, y=71.00, z=-4093.47], to['Skeleton'/3925726, l='MpServer', x=-3549.50, y=23.00, z=-4142.50]]
Retry entities: 0 total; []

– System Details –
Details:
Minecraft Version: 1.6.1
Operating System: Windows XP (x86) version 5.1
Java Version: 1.7.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 43297864 bytes (41 MB) / 140259328 bytes (133 MB) up to 1037959168 bytes (989 MB)
JVM Flags: 1 total; -Xmx1G
AABB Pool Size: 1060 (59360 bytes; 0 MB) allocated, 277 (15512 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 1.6.1
LWJGL: 2.9.0
OpenGL: RADEON X300/X550 Series x86/SSE2 GL version 2.0.5695 WinXP Release, ATI Technologies 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: 215 (12040 bytes; 0 MB) allocated, 70 (3920 bytes; 0 MB) used