Hopper: java.lang.ClassCastException: cf cannot be cast to bx

java.lang.ClassCastException: cf cannot be cast to bx
	at by.c(SourceFile:111)
	at sr.a(SourceFile:186)
	at nn.f(SourceFile:1062)
	at abn.a(SourceFile:116)
	at abn.g(SourceFile:92)
	at sz.l_(SourceFile:75)
	at nn.V(SourceFile:1165)
	at abw.a(SourceFile:1347)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.a(SourceFile:1386)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.a(SourceFile:1386)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.h(SourceFile:1234)
	at js.h(SourceFile:364)
	at net.minecraft.server.MinecraftServer.t(SourceFile:471)
	at net.minecraft.server.MinecraftServer.s(SourceFile:406)
	at bkz.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:340)
	at hi.run(SourceFile:583)

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

Time: 9/13/13 4:42 PM
Description: Reading NBT data

java.lang.ClassCastException: cf cannot be cast to bx
	at by.c(SourceFile:111)
	at sr.a(SourceFile:186)
	at nn.f(SourceFile:1062)
	at abn.a(SourceFile:116)
	at abn.g(SourceFile:92)
	at sz.l_(SourceFile:75)
	at nn.V(SourceFile:1165)
	at abw.a(SourceFile:1347)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.a(SourceFile:1386)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.a(SourceFile:1386)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.h(SourceFile:1234)
	at js.h(SourceFile:364)
	at net.minecraft.server.MinecraftServer.t(SourceFile:471)
	at net.minecraft.server.MinecraftServer.s(SourceFile:406)
	at bkz.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:340)
	at hi.run(SourceFile:583)


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

-- Corrupt NBT tag --
Details:
	Tag type found: INT
	Tag type expected: BYTE
	Tag name: Time
Stacktrace:
	at by.c(SourceFile:111)
	at sr.a(SourceFile:186)

-- Entity being loaded --
Details:
	Entity Type: FallingSand (sr)
	Entity ID: 794
	Entity Name: Falling Block
	Entity's Exact location: -220.00, 71.00, 124.00
	Entity's Block location: World: (-220,71,124), Chunk: (at 4,4,12 in -14,7; contains blocks -224,0,112 to -209,255,127), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Entity's Momentum: 0.00, 0.00, 0.00
	Immitating block ID: 66
	Immitating block data: 0
Stacktrace:
	at nn.f(SourceFile:1062)
	at abn.a(SourceFile:116)
	at abn.g(SourceFile:92)
	at sz.l_(SourceFile:75)
	at nn.V(SourceFile:1165)
	at abw.a(SourceFile:1347)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.a(SourceFile:1386)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.a(SourceFile:1386)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)

-- Entity being ticked --
Details:
	Entity Type: MinecartRideable (sy)
	Entity ID: 148
	Entity Name: entity.MinecartRideable.name
	Entity's Exact location: -219.50, 71.50, 124.51
	Entity's Block location: World: (-220,71,124), Chunk: (at 4,4,12 in -14,7; contains blocks -224,0,112 to -209,255,127), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Entity's Momentum: 0.00, -0.00, 0.00
Stacktrace:
	at abw.h(SourceFile:1234)
	at js.h(SourceFile:364)

-- Affected level --
Details:
	Level name: World Of xXDevastationXx
	All players: 1 total; [jv['xXDevastationXx'/280, l='World Of xXDevastationXx', x=-216.88, y=72.73, z=109.99]]
	Chunk stats: ServerChunkCache: 751 Drop: 0
	Level seed: -675209087
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-188,64,232), Chunk: (at 4,4,8 in -12,14; contains blocks -192,0,224 to -177,255,239), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 267994 game time, 43751 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 74538 (now: false), thunder time: 74538 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.t(SourceFile:471)
	at net.minecraft.server.MinecraftServer.s(SourceFile:406)
	at bkz.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:340)
	at hi.run(SourceFile:583)

-- System Details --
Details:
	Minecraft Version: 1.6.3
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 37705992 bytes (35 MB) / 215871488 bytes (205 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 5520 (309120 bytes; 0 MB) allocated, 1975 (110600 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 1, tcache: 0, allocated: 3, tallocated: 63
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1353 (75768 bytes; 0 MB) allocated, 264 (14784 bytes; 0 MB) used
	Player Count: 1 / 8; [jv['xXDevastationXx'/280, l='World Of xXDevastationXx', x=-216.88, y=72.73, z=109.99]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.