With Apache, AllowOverride settings are required on the /var/www/roundcubemail
directory. You can configure this as follows:

# ln -s /var/www/conf/modules.sample/roundcubemail.conf \
        /var/www/conf/modules
# apachectl stop
# apachectl start

Next, follow /var/www/roundcubemail/INSTALL or /var/www/roundcubemail/UPGRADING
