including wordpress core from a non-web dir

Hey, i’m trying to run a script from /www/mydomain/subfolder/ – and i need to include wp-load.php in it.
Wordpress is installed in /www/mydomain/public_html/

However, it seems that wordpress thinks it’s not installed. And I seem to have tracked the isse down to the database settings (constants: DB_USER, etc) not being accessible by other files than wp-config.php itself

So – can anyone please help me – is there a way to include wordpress core thw way I’m trying to do it?