Had similar issues when first setting up a few weeks ago. Since then have had the most success by dropping roms
one at a time into their respective games directory and then doing a Scan for Games, one title at a time, instead of importing them with Add Games. Sometimes it doesn't work on the fist try, sometimes it doesn't work at all, but most of the time it has worked and am up to 389 working titles now, one by one.
