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' => '24,803', 'nb_visits' => '9,304', 'hits' => '30,400', 'nb_actions' => '29,996', 'revenue' => '81,164.25', 'previous_nb_pageviews' => '26,375', 'previous_nb_visits' => '10,251', 'previous_hits' => '31,943', 'previous_nb_actions' => '31,401', 'previous_revenue' => '92,534.35', )'. Try to call this method with the parameters '&format=original&serialize=1'; you will get the original php data structure serialized.