Much thanks to Sean, who helped me with my previous issue with Eye-Fi Center on my WHS - see the 'cant change folder' thread.
Since we resolved that issue the Center has been working fine with our 4GB card. I went to setup a second card, an older 2GB card and Eye-Fi Center does not recognize the card when its plugged in. The system itself recognizes the card, it shows up as an additional drive via the Computer window off the Start menu. I can move files on and off the card. I know the reader works because the 4GB card works fine.
Ive formatted the 2GB card and no change in behavior. Any way to get Eye-Fi Center to recognize this second card?