Comment 1 for bug 611226

Hello Ian!

The revealing message here is "hostname: Name or service not known" which means there is a DNS issue on your system.
"hostname -i" and "hostname -d" should get you going on debugging this. Also take a look at /etc/nsswitch.conf.

Of course the package installation shouldn't have barfed that badly, but you'll be running into trouble all the time if your mail server has DNS issues.

Cheers,
Antonio