I know the question has more than one year, but was the first thing that popped up on google with "phpmyadmin ec2". Here is a better way to do things.
Knowing that you have yum, the best way to act is to install it by yum.
The easy way is to activate it just to install the packages you want, like phpMyAdmin or MongoDB. Eg.
sudo yum --enablerepo=epel install phpmyadmin
and it should work.
EDIT (comment by @eric-brotto):
It also should be noted that this comes with the advantage of uninstalling via
(sudo) yum erase phpmyadmin
Eric Brotto Jun 8 at 16:22
Note, that this would install
/usr/share/phpmyadmin. To make it available in your web root, you would have to symlink it thus:
sudo ln -s /usr/share/phpmyadmin /var/www/html/phpmyadmin
There are two ways to use EPEL, one is above, the other is to activate it permanently, editing the file
/etc/yum.repos.d/epel.repo and where it says
enabled=0 we change it to
enabled=1, now you can
sudo yum install phpmyadmin.
Here you can see a package list for the EPEL repo, too.