Hello!!
First sorry for my English
I have a Sd with raspbmc + retropie.
I have done the modification of es_system.cfg file to recognize my hdd where I have the roms.
Emuletionstation find roms but when I want to play some either Mame, sega, nintendo I always see this error.
https://www.dropbox.com/s/ayr182rbqqppoc4/Sin%20t%C3%ADtulo.png?dl=0
thank you for your help