I receive the error "cannot load MySQL extension, please check PHP Configuration".
To connect to a MySQL server, PHP needs a set of MySQL functions called "MySQL extension". This extension may be part of the PHP distribution (compiled-in), otherwise it needs to be loaded dynamically. Its name is probably mysql(i).so or php_mysql(i).dll. phpMyAdmin tried to load the extension but failed.
Make sure that the extension files do exist in the folder which the "extension_dir" points to and that the corresponding lines in your php.ini are not commented out. See phpinfo() for where you can find those files.
Usually, on *ix systems the problem is solved by installing a software package called PHP-MySQL, libapache2-mod-php5, or something similar.