You didn't post an error, as I see it its just the command line for cdrecord.
Hm. Did you run the setup wizzard of K3b? (Are you same user as for burning data CDs?). What happens if you copy your "error" to a commandline and start it from there in a shell (don't forget the line wrapping symbol)? Sorry, but the information is insufficient for more ideas ... at least for me.