OK, maybe if I post this as a new thread I might stand a better chance of getting a response.
I have set up a home based server following "The Perfect Server Ubuntu 10.10 [ISPConfig 3]" guide. Since then I installed Roundcube Webmail in /var/www/mail and after some initial instillation problems everything works fine. I can access my Roundcube Webmail locally through 192.168.x.x/mail and like I said all works fine.
What I want to do is access my Roundcube Webmail through the internet at "mydomain.com/mailbox" mydomain.com was set up with ISPConfig 3 so it's physical location on the server is /var/www/clients/client1/web1/web or /var/www/mydomain.com/web.
The first method that was suggested to me was to create a file /etc/apache2/conf.d/roundcube.conf with the following content,
Alias /mailbox /var/www/mail
php_admin_value open_basedir /var/www/mail
Allow from all
Theory being that Roundcube could then be accessed from any domain on the server by appending /mailbox to the domain name. Using this method when I go to mydomain.com/mailbox I get "Internal Server Error 500".
I repaced this method with a symlink created in the mydomain.com/web directory using the command "ln -s /var/www/mail mydomain.com/web/mailbox" which appears to have created the symlink just fine and when I use the command "ls -l" in that directory the symlink appears to point to /var/www/mail but when I go to mydomain.com/mailbox I am again greeted with the "Error 500".