Hello Andrew!

  AG> The '-p' isn't needed in your case then.  You should
    > just add the following to /etc/rc.conf:
    >    dhclient_flags="-q ne0"
    >
    > Presumably that should stop the error messages...

It certainly seems to, thanks!

[custom kernel]
  AG> It would free up RAM as well, since you can remove
    > tons of stuff you don't need.  The rc.conf change is
    > quicker and will confirm whether the error still
    > happens.

I downloaded comp.tgz with a possible view to building a
custom kernel.  Unfortunately I couldn't install it due to
lack of disk space.  If I can wrap my head around fdisk,
disklabel and mkfs then I may be able to add some disk space
to this machine.  Failing that, I may even be able to build
it on my (slightly more spacious) machine at home and
install it somehow on this one.

Thanks again for the suggestion, which seems to have done
the trick.  Thanks also to Steven, Nigel, and the two Jeffs
for their help.

Regards,
  - Andy Ball.