Hi,
I can send you the updated file from the upcoming release, which will resolve this issue. You will have to replace it manually though:
– Open up the /code/wp-content/plugins/ajax-search-pro/includes/classes/Utils/FileManager.php file on your server (you can use the plugin file editor or FTP too)
– Replace it’s contents with this
– Save
Afterwards the warning message will disappear and is permanently fixed.