Regardless, I was getting this on all my package updates on Ubuntu.
$ sudo apt-get install yaws
sudo: unable to resolve host toughie
Reading package lists... Done
Building dependency tree
Reading state information... Done
yaws-chat yaws-mail yaws-wiki yaws-yapp
The following NEW packages will be installed:
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B/637kB of archives.
After this operation, 2138kB of additional disk space will be used.
Selecting previously deselected package yaws.
(Reading database ... 169590 files and directories currently installed.)
Unpacking yaws (from .../archives/yaws_1.73-2_i386.deb) ...
Setting up yaws (1.73-2) ...
hostname: Unknown host
chown: cannot access `/etc/yaws/*.pem': No such file or directory
dpkg: error processing yaws (--configure):
subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)
To be honest, I had no idea what *.pem files are. Apparently, they're for SSL, and the Ubuntu install can't figure out how to start the yaws server without your machine having the hostname set up correctly.