Problems writing data to the database #22

I have a problem to write some lines: Local file name, File type and File mirror to form for download file in wfdownloads/admin/downloads.php or too wfdownloads/submit.php. Write permissions set I have.
When I hand write the values directly into the database, so the site is displayed. But when they re-edit, after saving again disappear. I assume that the error is in storing data in the database. But I can not find the mistake. Please, what am I doing wrong?

XOOPS 2.5.9 beta1, PHP 7.1.1, MySQL 5.5.5-10.1.21-MariaDB, wfdownloads 3.23 rc5