When I log into the backend and navigate to Catalogue > Manage Product everything is working fine. When I click on a product I get a blank page, with a link to 'Create new video' and 'Add an attribute'.
Our setup is: ubuntu 12.04, nginx php5-fpm and varnish.
My nginx log is displaying this error:
*6711 FastCGI sent in stderr: "PHP message: PHP Fatal error: Call to a member function __toString() on a non-object in /var/www/clients/client1/web2/web/app/Mage.php on line 859" while reading response header from upstream, client: 18.104.22.168, server: www.example.com, request: "GET /index.php/admin/catalog_product/edit/id/801/key/918d6b60004194117d8783613d066922/ HTTP/1.1", upstream: "fastcgi://unix:/var/lib/php5-fpm/web2.sock:", host: "www.example.com", referrer: "https://www.example.com/index.php/admin/catalog_product/index/key/bcc1f51a9f74e1f425be8d93903f0949/"
Can anyone help with problem as I'm really stuck?