After installing the last update 3.5.2. I get the following error
Fatal error: Call to undefined function is_site_admin() in /home/humanvoi/public_html/tus.gr/tusis/wp-content/plugins/wordpress-related-posts/related-posts.php on line 81
I can see the whole page and contents like I am a reader, but I cannot do anything as an owner of this site cos I get a blank page with the error above and yes it shows me signed in ...
I hadn't had an update installed since 2009 ...
Please help me,
thank you in advanced !!
