some minecarts with hoppers are driving on an interrupted rail then minecraft goes down with the bug report: Ticking entity

---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 20.01.13 18:25
Description: Ticking entity

java.lang.ArrayIndexOutOfBoundsException: -1
	at aar.a(SourceFile:314)
	at aar.e(SourceFile:535)
	at yv.r(SourceFile:1579)
	at apa.b(SourceFile:290)
	at apa.b(SourceFile:270)
	at apa.a(SourceFile:168)
	at qn.aB(SourceFile:97)
	at qn.l_(SourceFile:90)
	at yv.a(SourceFile:1312)
	at iq.a(SourceFile:480)
	at yv.g(SourceFile:1290)
	at yv.h(SourceFile:1197)
	at iq.h(SourceFile:374)
	at net.minecraft.server.MinecraftServer.r(SourceFile:460)
	at net.minecraft.server.MinecraftServer.q(SourceFile:395)
	at bhc.q(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:329)
	at gi.run(SourceFile:565)


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

-- Head --
Stacktrace:
	at aar.a(SourceFile:314)
	at aar.e(SourceFile:535)
	at yv.r(SourceFile:1579)
	at apa.b(SourceFile:290)
	at apa.b(SourceFile:270)
	at apa.a(SourceFile:168)
	at qn.aB(SourceFile:97)
	at qn.l_(SourceFile:90)
	at yv.a(SourceFile:1312)
	at iq.a(SourceFile:480)
	at yv.g(SourceFile:1290)

-- Entity being ticked --
Details:
	Entity Type: MinecartHopper (qn)
	Entity ID: 608712
	Entity Name: entity.MinecartHopper.name
	Entity's Exact location: NaN, -4,17, NaN
	Entity's Block location: World: (0,-5,0), Chunk: (at 0,-1,0 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)
	Entity's Momentum: 0,00, -0,75, -0,00
Stacktrace:
	at yv.h(SourceFile:1197)
	at iq.h(SourceFile:374)

-- Affected level --
Details:
	Level name: ChickenFarmAuto1
	All players: 1 total; [it['Joooniii'/383158, l='ChickenFarmAuto1', x=1647,14, y=58,62, z=812,28]]
	Chunk stats: ServerChunkCache: 521 Drop: 0
	Level seed: 4980959556328655974
	Level generator: ID 01 - flat, ver 0. Features enabled: true
	Level generator options: 2;7,3x1,52x24;2;
	Level spawn location: World: (1636,4,817), Chunk: (at 4,0,1 in 102,51; contains blocks 1632,0,816 to 1647,255,831), Region: (3,1; contains chunks 96,32 to 127,63, blocks 1536,0,512 to 2047,255,1023)
	Level time: 55681 game time, 55681 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 140028 (now: false), thunder time: 106778 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.r(SourceFile:460)
	at net.minecraft.server.MinecraftServer.q(SourceFile:395)
	at bhc.q(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:329)
	at gi.run(SourceFile:565)

-- System Details --
Details:
	Minecraft Version: 13w03a
	Operating System: Mac OS X (x86_64) version 10.8.2
	Java Version: 1.6.0_37, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 2200434680 bytes (2098 MB) / 2690777088 bytes (2566 MB) up to 3162177536 bytes (3015 MB)
	JVM Flags: 3 total; -Xbootclasspath/a:/System/Library/PrivateFrameworks/JavaApplicationLauncher.framework/Resources/LauncherSupport.jar -Xms2512M -Xmx3024M
	AABB Pool Size: 725 (40600 bytes; 0 MB) allocated, 474 (26544 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 876 (49056 bytes; 0 MB) allocated, 212 (11872 bytes; 0 MB) used
	Player Count: 1 / 8; [it['Joooniii'/383158, l='ChickenFarmAuto1', x=1647,14, y=58,62, z=812,28]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

Only downloaded and played.