i would concur with WiFiJeff's recommendation, completely. i had read that about SanDisk 4GB cards (some of them having a switch to determine what kind of partition). also, if the CF card has said switch, and you have to change it to set it to the $GB FAT32 partition, i'd recommend formatting the card as well (yes, formatting it yet again), and turning off the R-1 and doing turning it back on again.
i would have to think it could very well be a bum CF card, though, as even Edirol suggests using SanDisk brand CF cards for the R-1 unit.