Nope still getting this. I added "Demul Arcade" as the platform from scratch and everything. It's a bummer because I feel like were so close to figuring this out.
Naomi games run directly from Demul no problem. When I add them to Launchbox and try to run one I get an error as if it can't find a rom in the dc romset. I'm so lost as what to try next. As far as I know all the parameters/settings are correct.