i have installed the mamece3 onto my storage card in this format:

/storage card/mamece
/storage card/mamece/roms

i tried to install on rom game into the roms directory in its zipped format. i start mamece3 and no games show up in the window. not sure if thats how its supposed to be. so i click on options and then show all games check mark. then a whole bunch of games show up. the rom image i installed was frogger. so i scroll down to frogger and click on play. the screen goes blank for a while and then nothing. what am i doing wrong?