The php_pdo_mysql.dll can\'t be enabled in machine. I have set extension=php_pdo.dll and extension=php_pdo_mysql.dll enabled in php.in
php_pdo_mysql.dll
extension=php_pdo.dll
extension=php_pdo_mysql.dll
On an Windows Server 2012, Apache 2.4, php 5.4 installation, after trying everything else changing this worked...
PHPIniDir "C:\php\"
to
PHPIniDir "C:/php/"
...guh.