Angry Jew Cat - Banned for Life

Fatal error: Cannot use object of type WP_Error as array in /home/path/domains/domain.com/public_html/wp-includes/taxonomy.php on line 1010

anyone know whats causing htis? the error pops up after i click 'use this feed' in the feed finder page. if i skip passed back to the main syndication page, everything appears to work properly still, but i'm just curious what sort of issues this problem may present if left unfixed. any help is appreciated!