Try to launch the game from Launchbox instead of BigBox. Pick a game and set the emulator to be RL, then launch it. If it works let me know. If not, make sure that the front-end is set to Launchbox
Here is a guide: http://wiki.rlauncher.com/index.php?title=LaunchBox/BigBox
I got mine to work by first trying everything from Launchbox, then configured all my fades and keymappers, etc.
Good Luck!