there is no phpmyadmin.conf in /etc/apache2/conf-available/phpmyadmin

When the first prompt appears, apache2 is highlighted, but not selected. If you do not hit "SPACE" to select Apache, the installer will not move the necessary files during installation. Hit "SPACE", "TAB", and then "ENTER" to select Apache.

If you didn't do this, enter the following command:

sudo dpkg-reconfigure phpmyadmin

Select no to reconfiguring the database and then you will get the option to select Apache following the steps above.

Are you sure you followed this correctly?

When the first prompt appears, apache2 is highlighted, but not selected. If you do not hit "SPACE" to select Apache, the installer will not move the necessary files during installation. Hit "SPACE", "TAB", and then "ENTER" to select Apache.

This is a very important part of step one that i've overlooked before that can cause this problem

As another remedy you could try this:

From the docs: https://help.ubuntu.com/community/phpMyAdmin

If this does not work, then you can do the following to include the phpMyAdmin-shipped Apache configuration into Apache:

sudo ln -s /etc/phpmyadmin/apache.conf /etc/apache2/conf.d/phpmyadmin.conf
sudo /etc/init.d/apache2 reload

Since Ubuntu 13.10 (Saucy Salamander), Apache no longer loads configuration files from the /etc/apache2/conf.d directory. Instead, they are placed in the /etc/apache2/conf-available directory which is managed with the a2enconf command. Therefore, if you need to manually include the phpMyAdmin-shipped Apache configuration file, you must run the following:

sudo ln -s /etc/phpmyadmin/apache.conf /etc/apache2/conf-available/phpmyadmin.conf
sudo a2enconf phpmyadmin
sudo /etc/init.d/apache2 reload