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
check that pdo*.dll files are in appropriate locations in OS directory, check references for these files are enabled in php.ini, check your dbconnection string is correct, restart apache