Signatures are working fine now.
As for the "$_ENV['HOSTNAME']" has no value. I am unsure why as the server has a hostname. I am a little confused as to why it is used as I can set the hostname of the server to anything... including "bleh"
asdf:~# hostname bleh
So I just added this line to config-inc.php: $_ENV['HOSTNAME'] = 'bleh';
Which matches the server config.
All seriousness Ive put it back to a domain-name but I do not understand why this is used?