Just a thought, because /dev/hdc seems like it thinks it's another hard drive (something to do with being plugged in as a slave off the back of /dev/hda (which would be a primary hard drive)
Erm I don't quite know how you'd check but if the device is a cdrw (as opposed to a cdrom) it might need to be looking at something with "scsi emulation". Previous versions of mandrake needed that for cdrw's and I'd previously had my kscd pointing at /dev/scd0 (plus the revised version of mandy then had to look at /dev/scd1 - dunno why). It could be that, though from memory, it could also just depend on which version/type of scsi emulation it could possibly be using, i.e. one is called scd, then there's another called sg?
Oh yes, you might be able to see that from using a /root terminal session (su, then root passwd etc) and doing the command "lsmod" to see if you're using a scsi module of some sort ?????
Sorry if that's all a bit irrelevant, it's all I can think of off the top of my head (currently befuddled by a couple of bottles of vino - my bro and family have just visited for first time in about 18 months - hic !).
Oh and I'd have to guess that it wouldn't be a system wide volume thing, because you've got sound from kaffeine, but what about the volume control for kscd itself??