Edit Lan Server

When I clicked edit on a lan server this what happened

Minecraft has crashed!      
      ----------------------      

Minecraft has stopped running because it encountered a problem; Updating screen events

A full error report has been saved to C:\Users\lionel\AppData\Roaming\.minecraft\crash-reports\crash-2013-03-22_19.40.00-client.txt - Please include a copy of that file (Not this screen!) if you report this crash to anyone; without it, they will not be able to help fix the crash :(



--- BEGIN ERROR REPORT d6b8d95f --------
Full report at:
C:\Users\lionel\AppData\Roaming\.minecraft\crash-reports\crash-2013-03-22_19.40.00-client.txt
Please show that file to Mojang, NOT just this screen!

Generated 3/22/13 7:40 PM

-- Head --
Stacktrace:
	at java.util.ArrayList.rangeCheck(Unknown Source)
	at java.util.ArrayList.get(Unknown Source)
	at beb.a(SourceFile:51)
	at axa.a(SourceFile:170)
	at axr.a(SourceFile:72)
	at axr.d(SourceFile:127)
	at axr.m(SourceFile:111)

-- Affected screen --
Details:
	Screen name: axa
Stacktrace:
	at net.minecraft.client.Minecraft.l(SourceFile:1078)
	at net.minecraft.client.Minecraft.K(SourceFile:574)
	at net.minecraft.client.Minecraft.run(SourceFile:526)
	at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
	Minecraft Version: 1.5.1
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_07, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 383672936 bytes (365 MB) / 514523136 bytes (490 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 2 total; -Xms512m -Xmx1024m
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	LWJGL: 2.4.2
	OpenGL: AMD Radeon HD 6310 Graphics   GL version 4.1.10834 Compatibility Profile Context, ATI Technologies Inc.
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Texture Pack: Default
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

java.lang.IndexOutOfBoundsException: Index: 28, Size: 28
	at java.util.ArrayList.rangeCheck(Unknown Source)
	at java.util.ArrayList.get(Unknown Source)
	at beb.a(SourceFile:51)
	at axa.a(SourceFile:170)
	at axr.a(SourceFile:72)
	at axr.d(SourceFile:127)
	at axr.m(SourceFile:111)
	at net.minecraft.client.Minecraft.l(SourceFile:1078)
	at net.minecraft.client.Minecraft.K(SourceFile:574)
	at net.minecraft.client.Minecraft.run(SourceFile:526)
	at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT 98047d9a ----------