Error: Data structure returned is not convertible in the requested format: Only integer keys supported for array columns on base level. Unsupported string 'totals' found for row 'array ( 'nb_pageviews' => false, 'nb_visits' => '1,954', 'hits' => false, 'nb_actions' => '0', 'revenue' => false, 'previous_nb_pageviews' => false, 'previous_nb_visits' => '10,173', 'previous_hits' => false, 'previous_nb_actions' => '0', 'previous_revenue' => false, )'. Try to call this method with the parameters '&format=original&serialize=1'; you will get the original php data structure serialized.