java.lang.NullPointerException: Ticking entity

---- Minecraft Crash Report ----
// Hi. I'm Minecraft, and I'm a crashaholic.

Time: 7/30/14 9:29 PM
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
	at aay.l(SourceFile:207)
	at aay.k(SourceFile:155)
	at xl.bE(SourceFile:450)
	at xk.l(SourceFile:1430)
	at xl.l(SourceFile:316)
	at afc.l(SourceFile:39)
	at afm.l(SourceFile:151)
	at xk.j(SourceFile:1298)
	at xl.j(SourceFile:194)
	at afc.j(SourceFile:44)
	at aqh.a(SourceFile:1410)
	at qo.a(SourceFile:601)
	at aqh.g(SourceFile:1388)
	at aqh.i(SourceFile:1281)
	at qo.i(SourceFile:479)
	at net.minecraft.server.MinecraftServer.y(SourceFile:606)
	at pk.y(SourceFile:303)
	at net.minecraft.server.MinecraftServer.x(SourceFile:530)
	at net.minecraft.server.MinecraftServer.run(SourceFile:446)
	at java.lang.Thread.run(Unknown Source)


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

-- Head --
Stacktrace:
	at aay.l(SourceFile:207)
	at aay.k(SourceFile:155)
	at xl.bE(SourceFile:450)
	at xk.l(SourceFile:1430)
	at xl.l(SourceFile:316)
	at afc.l(SourceFile:39)
	at afm.l(SourceFile:151)
	at xk.j(SourceFile:1298)
	at xl.j(SourceFile:194)
	at afc.j(SourceFile:44)
	at aqh.a(SourceFile:1410)
	at qo.a(SourceFile:601)
	at aqh.g(SourceFile:1388)

-- Entity being ticked --
Details:
	Entity Type: Skeleton (afm)
	Entity ID: 648796
	Entity Name: Skeleton
	Entity's Exact location: 245.58, 78.00, 191.58
	Entity's Block location: 245.00,78.00,191.00 - World: (245,78,191), Chunk: (at 5,4,15 in 15,11; contains blocks 240,0,176 to 255,255,191), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Entity's Momentum: -0.07, -0.08, -0.01
	Entity's Rider: ~~ERROR~~ NullPointerException: null
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at aqh.i(SourceFile:1281)
	at qo.i(SourceFile:479)

-- Affected level --
Details:
	Level name: Riverside
	All players: 3 total; [qr['Bleumunkie'/445412, l='Riverside', x=-796.86, y=72.00, z=2402.25], qr['mmmBoost'/599336, l='Riverside', x=28.20, y=69.00, z=614.74], qr['Lichtsprecher'/643715, l='Riverside', x=231.18, y=80.02, z=182.30]]
	Chunk stats: ServerChunkCache: 855 Drop: 0
	Level seed: 11597254
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: 308.00,77.00,265.00 - World: (308,77,265), Chunk: (at 4,4,9 in 19,16; contains blocks 304,0,256 to 319,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 13954576 game time, 355123 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 164334 (now: false), thunder time: 134393 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.y(SourceFile:606)
	at pk.y(SourceFile:303)
	at net.minecraft.server.MinecraftServer.x(SourceFile:530)
	at net.minecraft.server.MinecraftServer.run(SourceFile:446)
	at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
	Minecraft Version: 14w31a
	Operating System: Windows Server 2012 (amd64) version 6.2
	Java Version: 1.7.0_55, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 41679995992 bytes (39749 MB) / 42948100096 bytes (40958 MB) up to 42948100096 bytes (40958 MB)
	JVM Flags: 2 total; -Xmx40G -Xms40G
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Profiler Position: N/A (disabled)
	Player Count: 3 / 30; [qr['Bleumunkie'/445412, l='Riverside', x=-796.86, y=72.00, z=2402.25], qr['mmmBoost'/599336, l='Riverside', x=28.20, y=69.00, z=614.74], qr['Lichtsprecher'/643715, l='Riverside', x=231.18, y=80.02, z=182.30]]
	Is Modded: Unknown (can't tell)
	Type: Dedicated Server (map_server.txt)