my game crashed right after using command /summon to spawn things

Right after i typed:

/summon Minecart ~ ~ ~ {Riding:{id:Pig}} 

Minecraft freezes for about 1 second,then crashes.It happened on a world open to LAN and not open to LAN. When I did the command above on a world hosted on LAN by someone else,their(the person who hosted the world) Minecraft crashed.They have windows 8.1. Happened more then 3 times.Not modded.