You should only import the .cue files into Launchbox, that could be the issue there. My suggestion would be to delete the platform then re-import with just the .cue's when you get to the media download screen uncheck everything as you already have it all, so the import will be very quick. Also i should ask what core you are using in retroarch, and that is the same one you are using in Launchbox, i think there are 2 beetle psx cores a hardware one and a software one, are you deffinately using the correct one in Launchbox.