It was brought to my attention that I should summarise
the solution to this issue rather than just thank
people.

Summary:

Problem was a [host.time] Error 9 each time I tried to
run a ypmake to update the hosts table.

Other symptoms of the problems:

ypinit -m would complain that it couldn't find
domainname in the path.

Fix:

The problem was related a libc/domainname bug and was
fixed by implementing patch 112138-01.

Jim
Great stuff seeking new owners in Yahoo! Auctions!
http://auctions.yahoo.com