Because Kloxo-MR 6.5.0 still running php52s, phpmyadmin latest version (4.1.x) not work. You need Kloxo-MR 6.5.1 because running under php53s. Or downgrade kloxomr-thirdparty-phpmyadmin.
webmail already set if you create dns template and then using this template for dns setting. Because for 'special' purpose, you can not create subdomain with prefix webmail/cp/mail/www (example webmail.mysite.com).