Put the summary of the bug you're having here

What I expected to happen was...:
The commandblock places one double_plant-block (6) in the air 4 blocks above the commandblock

What actually happened was...:
The game crashed and everytime you tried to load the map it crashed

Steps to Reproduce:
1.: generate a new world (creative)(1.7.2; I didnt try other versions)
2.: place a commandblock (you can use the chat too)
3.: write this in the commandblock: " /setblock ~ ~4 ~ 175 6 " (175 is the double_plant-block)
4.: activate the commandblock
5.: the game will crash
6.: if you try to load the map it will crash every time.