Yes, all VANILLA. No mods. No mods that are often not considered as such. No plugins, no texture packs, pretty standard render settings.

Minecraft client 1.7.4
Connected to Minecraft server 1.7.4 (vanilla)

What I expected to happen was...:
Nothing special would happen, if anything

What actually happened was...:
Minecraft crashed!

Description: Rendering Block Entity
java.lang.NullPointerException: Rendering Block Entity
	at afh.a(SourceFile:110)
	at afh.h(SourceFile:236)
	at bni.a(SourceFile:20)
	at bni.a(SourceFile:15)
	at bni.a(SourceFile:10)
	at bnd.a(SourceFile:100)
	at bnd.a(SourceFile:92)
	at bmt.a(SourceFile:383)
	at bmm.a(SourceFile:994)
	at bmm.b(SourceFile:814)
	at azi.ah(SourceFile:787)
	at azi.f(SourceFile:711)
	at net.minecraft.client.main.Main.main(SourceFile:152)

Steps to Reproduce:
[In Minecraft 1.7.4 connected to Minecraft Server 1.7.4]

1. Place a command block, set to command setblock ~ ~1 ~ minecraft:mob_spawner 0 replace {EntityId:Zombie,SpawnData:{Equipment:[

]},SpawnPotentials:[{Type­:Skeleton,Weight:1,Properties:{Equipment­:[{},{},{},{},

]}}],SpawnCount:2,S­pawnRange:3,RequiredPlayerRange:64,Delay­:10,MinSpawnDelay:10,MaxSpawnDelay:100,M­axNearbyEntities:2}
2. Run command from it
3. Wait

This may only work with stuff copied from youtube. It seems to add a few bugged characters. First copied from http://www.youtube.com/watch?v=TKqhUGLKRo4 codes the last setblock one in the about section.

I hope I attached the proper crash log.

If you want to try connecting to the server where the issue is happening, its XX.XXX.XXX.XX, just outside the spawn area. Im not going to worry about griefing as I don't have much and its all protected. (Wont work if I manage to fix it using mcedit or something. No, I didn't use it on the map before the bug happened nor anything similar)

I got sick of waiting, download of the world is now provided, and I fixed the issue on my server's world using MCEdit. The world given is not edited.

Also, once its verified Ill fix it server side, I just know you guys most likely want to be able to see it for yourselves.