Ok I've had a play. I am using an official Canon PCMCIA Adaptor Card and a 256MB Compact Flash. Pictures taken on the Canon A70 in best detail/resolution.
Inserted the card, switched on the machine and went to Functions/JPEG. The Input was already selected to "PC Card 100Canon". The "100Canon" seems to be the folder in which all photos taken on the A70 are stored. Copying them to DVD-RAM was easy - just used the copy option.
I also managed to copy pictures to the Compact Flash card. Changed "Input" to the DVD-RAM (onto which I had copied several pictures) and selected several files for copy (a small green tick appears on select photos). Then selected the destination folder as the PC Card - by default it wanted to create a new folder but I just selected the existing "100Canon" one. Copied the selected files onto the Compact Flash which is now visible on either the PC, DVDR or on the camera itself. So a two way process does seem to work.
Have you tried using the format option on the DVDR? Goto Functions/JPEG/Others (you need to scroll down for this option) and select format. This will wipe the CF, you can then use it in your camera to take pictures and all should work.
Does any of this info help?