When I open "http://localhost/phpmyadmin/", enter "root" as the user name and my MySQL root password and press go, then if I was using Firefox, I was getting offered to download index.php file (of a zero length), if I was using Opera 11, it said "Connection closed by remote server".

Following recommendations I've removed all packages related to phpMyAdmin, PHP, MySQL and Apache and then reinstalled them step-by step (instead of just issuing apt-get install phpmyadmin and relying on the system to install the whole LAMP stack via dependencies as I've done before). The only change I've got was Firefox to stop offering to download index.php - now when I press Ok to submit my password, it just doesn't show any visible reaction at all.

What may the reason be and how to fix it?

I use up-to-date Xubuntu 11.04. Reinstalling the whole LAMP stack and phpMyAdmin did not help, neither did removing AppArmor.

I've tried to use SQLBuddy instead, but there's exactly the same problem. So, I think, the problem is not in phpMyAdmin but in MySQL, Apache or something.

MySQL seems to work if I use command line to access it. Apache & PHP seems to work also, as the login page of phpMyAdmin displays correctly.