It's strange it does this, if you are on the latest updated firmware do you have XBMC/Kodi as well as DBMC. Try installing the retro on XBMC/Kodi see how it goes...
If it's OK then just clear data in DBMC to free some space on your box.
It's nice having nice pics on the menus, but it's the contents of kodi you want and sometime the most simple way is the best.