It only stores filename in database tables that is plain string (no upload process in it)
Upload process is same irrespective of any database and it is done on PHP side.

Please confirm if there is some JS error in debug console F12.
Send screenshot if any.

In screenshot, i can see a warning. So first way is to disable the warnings in php,ini.

Second, edit the jqgrid_dist.php and find "mkdir" and put if file_exists condition above it.

if(!file_exists($uploads_dir))
@mkdir($uploads_dir,0755,true);