Hello again, I've spent most of the day trying to get this format right. Would somebody be so kind as to look at it for me and advise what will immediately become blazingly obvious? Aptitude advises that the problem is in line 5 and I believe it because aptitude is smarter than I am. Wisdom comes with age and I'm not quite sixty yet.
I've moved things around until I'm giddy and posting the answer back to the list is fine as, in the interim, I've cleared up the backlog of 10,000 emails. Regards and thanks, David Palmer.
# deb cdrom:[Debian GNU/Linux 4.0 r4 _Etch_ - Official amd64 DVD Binary-1 20080726-23:51]/ etch contrib main deb http://ftp.au.debian.org/debian stable main contrib non-free deb http://ftp.au.debian.org/debian dists/stable-updates/ deb http://security.debian.org/ etch/updates main contrib non-free