I am also having the same problem.... I can launch the games directly through retroarch but when I select a game through launchbox it will load reicast into the add date and time page ... which is not saving...but not the rom itself. I have added the platform by editing the retroarch emulator in the manage emulators page .. adding the platform Seag Dreamcast and -L "cores
eicast_libretro.dll" into the command line parameters. I then went and selected all games and made sure that the emulator for all games is retroarch... am I missing something?