Here is the offending query and error message from content_folder__delete.
-- check if the folder contains any items
select count(*) into v_count from cr_items
where parent_id = delete__folder_id;
if v_count > 0 then
v_path := content_item__get_path(delete__folder_id, null);
raise EXCEPTION ''-20000: Folder ID % (%) cannot be deleted because it is n
ot empty.'', delete__folder_id, v_path;
end if;
From my log, it shows that content_item__delete ran with no error message.
I will check-in this code, this is broken in previous versions anyway, it was never tested.