I am actually having the same issue. I have the Xmame and Xmaeme UI installed, ROMS are loaded in the roms directory on my MMS card, and have tried 5 roms so far, all getting the 'Unable to load ROM' msg. I checked the zipped ROMs, and they all have odd files in there, so don't know if they are the 'right' files.

Please let me know if you have any suggestions - am very anxious to get this working!! Gotta love the 770!!

Thanks in advance for any assistance (btw, my 1st post - just got the unit yesterday! This forum has been a great resource so far...)