SMF CB plugin breaking login and misdirecting logout

Hi,

I need to publish the SMF CB plugin in order to keep the user data in SMF up-to-date, but when I switch it on, it causes problems logging in and out of Joomla.

I'm using ProxyPass and ProxyPassReverse in Apache to direct users to the server with Joomla on. This works fine when SMF CB is unpublished, but when I publish it causes the login process to redirect to

https://<domain>/<forum>/http://<ipaddress>:81/<forum>/
instead of
https://<domain>/<forum>/

It also changes the logout URL. Instead of going to the forum root index.php, it goes to index.php?option=com_smf&Itemid=277& - my SMF forum page - so that anyone logging straight back in gets the forum.

Any help appreciated. My versions are:

Joomla 1.0.12
SMF 1.1.2
Joomla-SMF 2.0.2
Community Builder 1.0.1
SMF CB plugin 2.0.3
PHP 5.1.6
MySQL 4.1

Thanks,
Will