This begs the question of how you ran it, if you didn't bother to look for a device node (which would be in devfs syntax, so not /dev/hda). IIRC, cfdisk has to be told the device to run on, you must have told it something or it would have given you a usage message.
Sorry, I'm not quite familiar with the DevFS syntax. You mean /dev/discs/discX addressing?
I ran cfdisk with cfdisk /dev/hda, just as I'm used to it. Florian