I am getting this error message in the sidebar of one of my posts. This seems to have been an issue after I have upgraded to WP 3.0 and then the newer version, but I haven't noticed it until now. I have checked with my host and they are not seeing any issues. I have changed the cache and subfolder to 777 and am hosting with Bluehost and the theme I am using is Infocus.
Fatal error: Using $this when not in object context in /home2/mandiell/public_html/cocoonwebdesign/wp-includes/default-widgets.php on line 537