This may have been caused by your SD card not having enough space. One thing you MUST do before attempting to add any ROMs is expand the file system on your SD card. You can do this most simply by entering “sudo raspi-config” from the terminal. From the resulting menu, you can expand the file system. Or you can consult this link: http://xmodulo.com/configure-raspberry-pi-first-time.html
It’s important that you expand your file system BEFORE doing anything else. If you attempt to do so later it will not work. Period.
I am not a linux guru, I learned all of this the hard way.