I'm not familiar with this product, but it has piqued my interest in finding out why it might not work with your PC.
Could you detail a bit more about your PC specification (motherboard make/model etc).
Also if you have any more specific information on why Matrox claim it might not work with your system. (Incompatibility with components, etc)
I had a quick look at the Matrox web site, but as I'm at work I didn't have enough time to find it (well not before the boss walked by)! So any links would be appreciated.