I think that's it. It looks like a LOT of roms are too big to be double-sized. I don't know what exit code xmame is returning but.. it would be very helpful if xmaeme could display something descriptive of the problem. Otherwise, I think a lot of people will just give up on xmaeme (and probably xmame in the bargain).

On a related point, xmaeme doesn't seem to be checking the xmamerc file for rom and sample paths. I've updated my own xmamerc so xmame knows where to find my roms and samples (not the original paths) but in xmaeme I still have to "browse" to find them.