Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at abw.a(SourceFile:2184)
	at sr.l_(SourceFile:109)
	at abw.a(SourceFile:1349)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)

---- Minecraft Crash Report ----
// Don't do that.

Time: 9/20/13 9:47 PM
Description: Ticking entity

java.lang.NullPointerException
	at abw.a(SourceFile:2184)
	at sr.l_(SourceFile:109)
	at abw.a(SourceFile:1349)
	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:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at abw.a(SourceFile:2184)
	at sr.l_(SourceFile:109)
	at abw.a(SourceFile:1349)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)

-- Entity being ticked --
Details:
	Entity Type: FallingSand (sr)
	Entity ID: 301125
	Entity Name: §6Falling Block
	Entity's Exact location: -299.50, 73.00, 99.50
	Entity's Block location: World: (-300,73,99), Chunk: (at 4,4,3 in -19,6; contains blocks -304,0,96 to -289,255,111), 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: 225
	Immitating block data: 0
Stacktrace:
	at abw.h(SourceFile:1234)
	at js.h(SourceFile:364)

-- Affected level --
Details:
	Level name: New World
	All players: 1 total; [jv['CreeperKing0227'/301459, l='New World', x=-322.25, y=63.00, z=263.34]]
	Chunk stats: ServerChunkCache: 711 Drop: 0
	Level seed: 5734153319103053149
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-232,64,248), Chunk: (at 8,4,8 in -15,15; contains blocks -240,0,240 to -225,255,255), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 1480 game time, 1480 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 38427 (now: false), thunder time: 86377 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
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: 1.6.4
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 121543832 bytes (115 MB) / 281153536 bytes (268 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 4492 (251552 bytes; 0 MB) allocated, 1214 (67984 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1321 (73976 bytes; 0 MB) allocated, 334 (18704 bytes; 0 MB) used
	Player Count: 1 / 8; [jv['CreeperKing0227'/301459, l='New World', x=-322.25, y=63.00, z=263.34]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.