After many hours having a problem with PHP 5.1.6, virtualmin 3.79 and phpmyadmin 2.11.10 running on Centos 5.4 where I was unable to login into phpmyadmin using cookie authentication.
The problem was that after entering the credentials to login I got back to the login screen without any error message.
The problem was solved my changing the host from using fastcgi to mod_php at Server Configuration -> Website Options.
If you don’t have mod_php in the list, you might need to add the following two lines to the httpd.conf and restart httpd:
LoadModule php5_module modules/libphp5.so
AddHandler php5-script php
Hope this help soneone…