Your form entry screen does not look normal. It says you have 3,661 items and you only see a handful? That's not normal without having a filter set, a software error, or a corrupt database. I would first check to make sure the data is actually in the database using PHPMyAdmin. If the record you can't see are in the wp_frm_items table, then the problem is likely not the database. Next, look for PHP or jQuery errors. Enable WordPress debug and take it through the normal documented WordPress troubleshooting steps. Make sure you're on the right PHP version.