Thanks to the not-so-helpful people at 1&1, when they moved Amibay to a new server (that magically CAN support php, wonders never cease) they write enabled the files that allowed the Blackhole exploit to hit the site again this morning.
Sorry about that, it wasn't directly our fault.
Amibay is all cleaned and protected again now, but we do intend to move to a new server in the near future.