I know it is a common problem and there are many solutions on the web but I'm trying everything and anything is working, I can't have phpmyadmin running on my machine. I installed XAMPP through:

sudo tar xvfz ./Downloads/xampp-linux-1.8.1.tar.gz -C /opt

then I did the chmod trick supposed to make an end to access issues and I change the default location to my php projects from /var/www to Dropbox/php.

Then I started XAMPP in the usual way:

sudo /opt/lampp/lampp start

When I tried to run one of my php projects the output on the web is fine but if for example I try to write localhost on my browser I get:

It works

and not the usual XAMPP interface and most of all when I try to access localhost/phpmyadmin I get the login page, insert username (root) and password and I get:

You don't have permission to access /phpmyadmin/index.php on this server.
Apache/2.2.22 (Ubuntu) Server at localhost Port 80

I tried the Required all granted trick and some others but nothing is working. I even tried to uninstall phpmyadmin and reinstall it but this is not working too. I don't know hot to proceed.

Thanks for your help.