Я исправил ошибку, разрешив / отредактировав следующую конфигурацию в php.ini
:
1st (uncomment и add config):
include_path = "C:\php\includes"
2nd (uncomment):
extension_dir = "ext"
3rd (uncomment и edit config):
extension=D:/PHP/ext/php_mysql.dll
extension=D:/PHP/ext/php_mysqli.dll