No, it won't make a difference if you use a mac
I use a mac, appleguru uses a mac

BFM means Boot From Media, basically its a bios which is formatted to be loaded from another bios, rather than booted to from flash.
You need to use non BFM bioses with the xenium (at least with current XOS releases)
There are virtually an infinite number of reasons why you could be getting a FRAG (flashing red and green). FRAG happens when the MCPX chip can't load a BIOS successfully.... but that could be for many reasons, including loose connections.
If you can see the XOS menus it means the connections are good :-\

Check the jumper settings on the HDD, make sure it's set to Cable Select. Make sure all your cables are plugged in....
Nah, not d0, the Xenium OS wouldn't load.. It's quite possible one or two of your LPC points arent making good contact, other than that I'm at a loss to think of anything.