> This will be called MAME_g.ini in the same folder as MAMEUI > is in.
Are you sure MAME_g.ini stores the game names you have the ROMs sets for (so the 'Available' list)?
I loaded that file in an editor and it contains all game names in the current MAME version I think. Also this line 'YOU CAN SAFELY DELETE THIS FILE TO RESET THE GAME STATS.' tells me it stores the game stats for each game.
Based on those things I saw, I think MAME_g.ini is not the 'Available' list of MAMEUI or there is something I don't understand...