Markus Amalthea Magnuson on "[Plugin: WordPress SEO by Yoast] Incorrect path for resources (image, js) after installing and activating"

It turns out this problem appears in other plugins as well.

The problem has to do with symlinks in the wp-content path, see this ticket for more information.

I solved it by editing my wp-config.php, replacing this:

define('WP_CONTENT_DIR',$_SERVER['DOCUMENT_ROOT'] . '/wp-content');

With this:

define('WP_CONTENT_DIR', realpath($_SERVER['DOCUMENT_ROOT'] . '/wp-content'));