its crashing my minecraft please Help! With new launcher!

---- Minecraft Crash Report ----
// Everything's going to plan. No, really, that was supposed to happen.

Time: 7/5/13 4:28 PM
Description: Ticking entity

java.lang.ClassCastException: java.lang.Byte cannot be cast to java.lang.Float
	at ol.d(SourceFile:91)
	at oc.aJ(SourceFile:520)
	at oc.R(SourceFile:709)
	at oc.x(SourceFile:165)
	at od.x(SourceFile:128)
	at nk.l_(SourceFile:272)
	at oc.l_(SourceFile:1138)
	at od.l_(SourceFile:169)
	at abr.a(SourceFile:1350)
	at abr.g(SourceFile:1328)
	at abr.h(SourceFile:1235)
	at atn.k(SourceFile:1374)
	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 ol.d(SourceFile:91)
	at oc.aJ(SourceFile:520)
	at oc.R(SourceFile:709)
	at oc.x(SourceFile:165)
	at od.x(SourceFile:128)
	at nk.l_(SourceFile:272)
	at oc.l_(SourceFile:1138)
	at od.l_(SourceFile:169)
	at abr.a(SourceFile:1350)
	at abr.g(SourceFile:1328)

-- Entity being ticked --
Details:
	Entity Type: Sheep (rw)
	Entity ID: 8334
	Entity Name: Sheep
	Entity's Exact location: 5.50, 67.00, -0.28
	Entity's Block location: World: (5,67,-1), Chunk: (at 5,4,15 in 0,-1; contains blocks 0,0,-16 to 15,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Entity's Momentum: 0.00, -0.08, 0.00
Stacktrace:
	at abr.h(SourceFile:1235)

-- Affected level --
Details:
	Level name: MpServer
	All players: 4 total; [bcx['AceRex1337'/126847, l='MpServer', x=1.50, y=67.72, z=-6.50], ben['bigblue302'/8517, l='MpServer', x=-1.50, y=64.09, z=0.50], ben['cheepcreeper'/8519, l='MpServer', x=-6.50, y=63.09, z=3.50], ben['bigwolfden'/3171, l='MpServer', x=-13.72, y=63.00, z=-9.47]]
	Chunk stats: MultiplayerChunkCache: 441
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (0,65,0), Chunk: (at 0,4,0 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: 6192 game time, 6432848 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: 26 total; [bcx['AceRex1337'/126847, l='MpServer', x=1.50, y=67.72, z=-6.50], ben['liamrory'/8334, l='MpServer', x=5.50, y=67.00, z=-0.28], rz['Squid'/8748, l='MpServer', x=-42.50, y=58.41, z=-35.50], rz['Squid'/8749, l='MpServer', x=-31.59, y=58.50, z=-38.53], tt['Zombie'/8269, l='MpServer', x=0.50, y=19.00, z=-49.50], tc['Creeper'/8811, l='MpServer', x=-36.50, y=13.00, z=-38.50], tc['Creeper'/8865, l='MpServer', x=-34.50, y=27.00, z=-33.50], ben['bigblue302'/8517, l='MpServer', x=-1.50, y=64.09, z=0.50], ben['cheepcreeper'/8519, l='MpServer', x=-6.50, y=63.09, z=3.50], ben['bigwolfden'/3171, l='MpServer', x=-13.72, y=63.00, z=-9.47], ben['bigblue302'/8517, l='MpServer', x=-1.50, y=64.09, z=0.50], ben['cheepcreeper'/8519, l='MpServer', x=-6.50, y=63.09, z=3.50], tt['Zombie'/8995, l='MpServer', x=-31.50, y=14.00, z=-27.50], to['Skeleton'/8527, l='MpServer', x=6.38, y=39.00, z=40.78], rv['Pig'/8701, l='MpServer', x=-16.88, y=65.00, z=39.50], rv['Pig'/8706, l='MpServer', x=-2.50, y=65.00, z=28.50], tt['Zombie'/8836, l='MpServer', x=-39.50, y=15.00, z=33.50], sp['item.item.rottenFlesh'/8174, l='MpServer', x=12.47, y=22.13, z=11.94], rw['Sheep'/8689, l='MpServer', x=23.97, y=70.00, z=-4.06], tq['Spider'/8921, l='MpServer', x=35.22, y=22.00, z=13.50], tc['Creeper'/7914, l='MpServer', x=6.97, y=42.00, z=26.66], tc['Creeper'/7717, l='MpServer', x=42.50, y=15.00, z=7.50], rw['Sheep'/8731, l='MpServer', x=4.50, y=67.00, z=-0.18], ben['bigwolfden'/3171, l='MpServer', x=-13.72, y=63.00, z=-9.47], rw['Sheep'/8674, l='MpServer', x=27.67, y=70.00, z=18.47], tc['Creeper'/8848, l='MpServer', x=-20.50, y=18.00, z=-31.50]]
	Retry entities: 0 total; []
Stacktrace:
	at bcu.a(SourceFile:284)
	at atn.b(SourceFile:1743)
	at atn.d(SourceFile:627)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.1
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_13, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 33011664 bytes (31 MB) / 152342528 bytes (145 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 41049 (2298744 bytes; 2 MB) allocated, 276 (15456 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: ATI Mobility Radeon HD 4200 Series      GL version 3.2.9704 Compatibility Profile Context, 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: 538 (30128 bytes; 0 MB) allocated, 167 (9352 bytes; 0 MB) used