Mailman web interface not changing settings

[lists]

Dear list,

I hope this is a valid question on this list, if not please
ignore me and I'll go bother the mailman people.

I have just installed Mailman 2.1.4 on a "4.9-RELEASE-p1 FreeBSD"
system, using portupgrade(upgrading from v2.1.1 - v2.1.4).

It runs fine from the command line but I can not use the web
interface to update list settings. Note, I could not use the web
interface in mailman v2.1.1 either, but I now *need* to have this
working.

I have set up httpd.conf as described in FreeBSD-post-install-
notes(for virtual hosts) and I am using sendmail as the MTA,
so I dont think I've veered to far from the norm in setup.

The web interface at http://www.vhost.com/mailman/admin/testlist
is up and running, and I can log in and out of the admin page. But
if I try to change any setting, then click on the
"submit your changes" button at the bottom of the page, the page
updates, but the settings all return to their initial values.

It seems to me that all parts of mailman are working, including the
web interface, but it simply does not update the config.

Anyone know why this may be? Permissions maybe?

Thanks for your time,

Stephen