[Mailman-Users] Domain repeated in URL

[mailman at mathesonuk.com]

I have recently set up a new installation of Mailman 2.1.5. All is 
working OK but the URLs generated in the admin interface have the 
domain name repeated.

e.g. In the main list webpage at 
http://mailman.mydomain.org/mailman/admin

The link to the Mailman list appears as:
http://mailman.mydomain.org/mailman/mailman.mydomain.org/admin/mailman

I have tried altering Defaults.py but can't seem to get it working.

Defaults.py includes:
DEFAULT_EMAIL_HOST = 'mydomain.org'
DEFAULT_URL_HOST = 'mailman.mydomain.org'
DEFAULT_URL_PATTERN = 'http://%s/mailman/'

# DEFAULT_HOST_NAME has been replaced with DEFAULT_EMAIL_HOST, 
however some
# sites may have the former in their mm_cfg.py files.  If so, we'll 
believe
# that, otherwise we'll believe DEFAULT_EMAIL_HOST.  Same for 
DEFAULT_URL.
DEFAULT_HOST_NAME = 'mydomain.org'
DEFAULT_URL = 'mailman.mydomain.org'

And my http.conf includes
<VirtualHost x.x.x.x>
ServerName mailman.mydomain.org
ServerAlias www.mailman.mydomain.org
DocumentRoot /usr/local/mailman
ScriptAlias /mailman/ /usr/local/mailman/cgi-bin/
Alias /pipermail/ /usr/local/mailman/archives/public/
<Directory /usr/local/mailman/archives/public>
Options +FollowSymLinks
</Directory>
</VirtualHost>

This is exactly the same configuration as on our previous server 
which worked fine.

Can someone point me in the right direction to sort this.

Many thanks,

Sandy Matheson