You don't need to mount the cd to write to it. A raw cd can't be mounted, as far as I know, as it has no file system to mount.
If there is a mounted cd in your drive, cdrdao won't be able to do it's stuff. Unmount it.
I find k3b hasn't got all the answers. It sometimes causes me grief, but then I just do it from a console. I have an open office file Copying_commands, which I keep in case I forget what to do. If you would like a copy, let me know, I'll send it over. I find copying from a console goes faster.