Error: Data structure returned is not convertible in the requested format: Multidimensional column values not supported. Found unexpected array value for column 'subcategories' in row '0': 'array ( 0 => array ( 'uniqueId' => 'VisitorInterest_Engagement', 'name' => 'Engagement', ), 1 => array ( 'uniqueId' => 'Transitions_Transitions', 'name' => 'Transitions', ), 2 => array ( 'uniqueId' => 'General_Downloads', 'name' => 'Downloads', ), 3 => array ( 'uniqueId' => 'Actions_SubmenuPagesEntry', 'name' => 'Entry pages', ), 4 => array ( 'uniqueId' => 'Actions_SubmenuPagesExit', 'name' => 'Exit pages', ), 5 => a'. Try to call this method with the parameters '&format=original&serialize=1'; you will get the original php data structure serialized.