apparently, the 2800 NEEDS a properly formatted card in the CF card slot to function. i had removed the card in attempt to use it in the H7600... so when i put it back in the 2880 it was no longer recognized.
i tried formatting the card on my mac, but it never worked (nor did formatting a card for the H7600 on my mac work, either)...
so i took the 2800 card and formatted it inside the H7600! and low-and-behold, that gave it the proper PC FAT16 format and now my 2800 works again