Try to make 'transition' for qmail. If qmail already exist so Kloxo-MR not convert to qmail-toaster. With this approach, I hope Kloxo-MR ready for upgrade from previous version and install on Centos 6 (no upgrade on Centos 6)!.
Yes, issues still related to qmail.
Another problem. Connection from my home have a problem again. I hope when Kloxo-MR ready to upload, connection back to normal.