Hi guys, I am getting the same error after updating to WP 3.4 However I cannot fix it based on manuals i find online. I do not have any file called db.php in wp-content/ folder. I do not use plugin called DB-Cache plugin . My site works for users just fine just in dashboard some functionality doesn't work such as Yoast's SEO plugin, updates etc. that's when I get the error.
Fatal error: Call to undefined method wpdb::delete() in .... >> "/public_html/plaveckyblog/wp-includes/option.php on line 370"
Do you know what might be the issue?