Error: Data structure returned is not convertible in the requested format: Only integer keys supported for array columns on base level. Unsupported string 'pageMetrics' found for row 'array ( 'loops' => 14, 'pageviews' => 244, 'entries' => 178, 'exits' => 124, )'. Try to call this method with the parameters '&format=original&serialize=1'; you will get the original php data structure serialized.