I vae the node_view system page for Organic Groups. The error is displayed always on the page:

Notice: Undefined property: stdClass::$subject w include() (line 1 in /sites/all/themes/omega/omega/templates/block.tpl.php).
Notice: Undefined property: stdClass::$subject w include() (line 5 in /sites/all/themes/omega/omega/templates/block.tpl.php).

The error is not diplayed in user_view system page.