Problems after 3.5 upgrade

That’s listed as a known problem from the upgrade — see this:

http://wordpress.org/support/topic/troubleshooting-wordpress-35-master-list?replies=4

Error message: Warning: Missing argument 2 for wpdb::prepare(), called in … (happens in themes and plugins)

Fix: Your site is fine, but you may wish to turn off PHP’s display errors setting. Contact your theme or plugin dev and point them to http://make.wordpress.org/core/2012/12/12/php-warning-missing-argument-2-for-wpdb-prepare/ so they can fix the underlying issue.

WordPress.ORG is not the author — see the theme page for author info:

http://wordpress.org/extend/themes/grey-opaque