Hopper: java.lang.IllegalArgumentException: Modifier name cannot be empty

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-191176/

Crash:

java.lang.IllegalArgumentException: Modifier name cannot be empty
	at org.apache.commons.lang3.Validate.notEmpty(Validate.java:398)
	at ot.<init>(SourceFile:31)
	at tp.a(SourceFile:94)
	at ye.D(SourceFile:580)
	at of.l_(SourceFile:1170)
	at uf.l_(SourceFile:203)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 20-9-13 16:30
Description: Ticking player

java.lang.IllegalArgumentException: Modifier name cannot be empty
	at org.apache.commons.lang3.Validate.notEmpty(Validate.java:398)
	at ot.<init>(SourceFile:31)
	at tp.a(SourceFile:94)
	at ye.D(SourceFile:580)
	at of.l_(SourceFile:1170)
	at uf.l_(SourceFile:203)
	at jv.h(SourceFile:185)
	at ka.a(SourceFile:190)
	at eu.a(SourceFile:136)
	at cn.b(SourceFile:64)
	at ka.e(SourceFile:60)
	at kd.b(SourceFile:37)
	at blc.b(SourceFile:84)
	at net.minecraft.server.MinecraftServer.t(SourceFile:489)
	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 org.apache.commons.lang3.Validate.notEmpty(Validate.java:398)
	at ot.<init>(SourceFile:31)
	at tp.a(SourceFile:94)
	at ye.D(SourceFile:580)
	at of.l_(SourceFile:1170)
	at uf.l_(SourceFile:203)

-- Player being ticked --
Details:
	Entity Type: null (jv)
	Entity ID: 70
	Entity Name: Kabds
	Entity's Exact location: -68,47, 6,00, -1456,66
	Entity's Block location: World: (-69,6,-1457), Chunk: (at 11,0,15 in -5,-92; contains blocks -80,0,-1472 to -65,255,-1457), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)
	Entity's Momentum: 0,00, -0,08, 0,00
Stacktrace:
	at jv.h(SourceFile:185)
	at ka.a(SourceFile:190)
	at eu.a(SourceFile:136)
	at cn.b(SourceFile:64)
	at ka.e(SourceFile:60)

-- Ticking connection --
Details:
	Connection: ka@adc40c
Stacktrace:
	at kd.b(SourceFile:37)
	at blc.b(SourceFile:84)
	at net.minecraft.server.MinecraftServer.t(SourceFile:489)
	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 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: 184816560 bytes (176 MB) / 431276032 bytes (411 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 21 (1176 bytes; 0 MB) allocated, 21 (1176 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: 5 (280 bytes; 0 MB) allocated, 5 (280 bytes; 0 MB) used
	Player Count: 1 / 8; [jv['Kabds'/70, l='Adverture Map Hogwarts', x=-68,47, y=6,00, z=-1456,66]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-191176/12601306/