Show error message

The solution to this problem is very simple:

Replace in db_prefix.php

wp_register_style('dbStyle',plugins_url('css/style.css',__FILE__));
wp_enqueue_style('dbStyle');
wp_register_script('jquery.validate',plugins_url('js/jquery.validate.min.js',__FILE__),array('jquery'), false, false);
wp_enqueue_script('jquery.validate');
wp_register_script('util',plugins_url('js/util.js',__FILE__),array('jquery'), false, false);
wp_enqueue_script('util');

by

function dbprefix_insertFrontEndScripts(){
wp_register_style('dbStyle',plugins_url('css/style.css',__FILE__));
wp_enqueue_style('dbStyle');
wp_register_script('jquery.validate',plugins_url('js/jquery.validate.min.js',__FILE__),array('jquery'), false, false);
wp_enqueue_script('jquery.validate');
wp_register_script('util',plugins_url('js/util.js',__FILE__),array('jquery'), false, false);
wp_enqueue_script('util');
}
add_action('wp_enqueue_scripts','dbprefix_insertFrontEndScripts');

Save and the error is gone

The problems where bigger than anticipated

The solution is still simple. Download Change DB Prefix 1.3 and install. This version is an improvement of the prior version. Gets rid of all the bugs and improves on the success and error handling.

Thanks, will check and update.