This message indicates that the directory specified does not exist.
The backup directory-name has been added to the database reference file.
Check that the directory-name and path specified are correct. If they are not correct, the entry should be removed from the database reference file (using the /e (erase) option and the Database Reference File Maintenance Utility) and the correct entry added to the database reference file using the same utility.
If the path and directory-name are correct, ensure that the directory is created or made available to the Fileshare Server before starting the Fileshare Server, so that the automatic backup can take place. If the directory does not exist, the Fileshare Server fails when trying to back up the recovery log file or the data files automatically when required to do so.