after fouling up my installation somehow, I deleted everything but the serendipity_config_local.inc.php file and the uploads folder, then grabbed the latest release, copied it into my blog folder, thinking everything would work again...
Wrong, it doesn't.
Everything that is handled by the permalink thingie (archives, full entries, tags, static pages, you name it) returns a 404 error. Which crucial step did I miss here? I guess it has something to do with the .htaccess somehow, but I can't repair it on my own..