Hi, in the new version of wordpress 3.7 all of those who upgrade to this version and installing WordPress SEO by Yoast have this problem as below:
Warning: Missing argument 3 for wpseo_upgrader_process_complete() in /home/xxxx/public_html/blog/wp-content/plugins/wordpress-seo/inc/wpseo-non-ajax-functions.php on line 259
If you try to update or install any plugin you will see this error.
this is will not effect your blog and we are waiting the developer of this plugin to solve it.
The reason for the failure is that WordPress 3.7 is only passing 2 parameters instead of 3 on a completion of an upgrade in file /wp-admin/includes/class-wp-upgrader.php
We are waiting with you the Yoast to fix this.