error in second step

Warning: Undefined variable $pdo in C:\xampp\htdocs\gibbon\installer\install.php on line 304

Also in step PHP Extension gd is Not Installed shows x

Hello, whilst I don’t have a lot of experience on Windows with XAMPP, I know Gibbon has been run in this environment, and so it is possible. From the error message it sounds to me like you might not have PHP’s PDO extension enabled, and so perhaps start by trying to work out how to check and adjust this. Cheers, Ross.