Boot up with the usb connected, holding start+select, it should go into the format menu, choose quick format and when it's finished it should then go straight into usb mode and connect up with your pc, allowing you to copy a xmenu.dat file over.
Lots of people think it's the game, but i can you it's not and play perfectly on even my oldie SC-CF. (check on-line vids, the top screen is not supposed to flash))
Try transfering the rom to the acekard ram.