It's maybe certain domain(s) using horde and or t-dah.
Latest Kloxo-MR remove horde (too old) and t-dah (dead project) and change to telaen.
Step:
1. remove old webmail with 'yum remove kloxomr-webmail-horde kloxomr-webmail-t-dah' and delete their directory with 'rm -rf /home/kloxo/httpd/webmail/horde' and 'rm -rf /home/kloxo/httpd/webmail/t-dah'
2. Add new webmail with 'yum install kloxomr-webmail-telaen'
3. Set all webmail on panel as '--chooser--'
4. To make sure your Kloxo-MR as 2013031825
5. Run 'sh /script/fix-all; sh /script/restart-all'