It does sound like it's the paths to your Connections and webassist folders that are incorrect. Sorry if I'm being too simplistic, but if your page is in the root of your site i.e. mysite.com/mypage.php and your Connections and webassist folders are also in the root, your links don't need any dots or slashed i.e.
<?php require_once('Connections/jodenonline_i.php'); ?>
<?php require_once("webassist/form_validations/wavt_scripts_php.php"); ?>
You would only need to include dots or slashes if the page was in a subfolder i.e. mysite.com/subfolder/mypage.php in which case the links would be:
<?php require_once('../Connections/jodenonline_i.php'); ?>
<?php require_once("../webassist/form_validations/wavt_scripts_php.php"); ?>
You can use an absolute link but this needs to include the full path to the page which depends on your hosting platform. To find this path, make a PHP file which contains only the following:
<?php
echo dirname(__FILE__);
?>
Name the file whereami.php and upload to your site, then open yoursite.com/whereami.php in a browser and it will give you the full path, which will be something like:
/var/www/vhosts/mysite.com/httpdocs
You can then use that path in your PHP code like this:
<?php require_once('/var/www/vhosts/mysite.com/httpdocs/Connections/jodenonline_i.php'); ?>
<?php require_once("/var/www/vhosts/mysite.com/httpdocs/webassist/form_validations/wavt_scripts_php.php"); ?>
You should remove the whereami.php file from your remote site once you've taken a note of the path, for security purposes.