Hi,
It means that the theme does not use the searchform.php (get_search_form) “method” to display the search bar at the desired location. The developer probably had a good reason to do so.
The only possibility in this case is to replace the search form manually, within the theme files directly. I usually suggest to contact the theme developer, but if you want, you can leave temporary back-end and FTP details, and I will try to locate the corresponding theme code.