This is my quick strip-down of the open.inc.php file... I would start from here... It is in no way guaranteed to work because i have not tested it.
Make sure to change the form action to the location of your open.php file****
<?php
if(!defined('OSTCLIENTINC')) die('Kwaheri rafiki!'); //Say bye to our friend..
$info=($_POST && $errors)?Format:($_POST)(); //on error...use the post data
?>
<form action="../support/open.php" method="POST" enctype="multipart/form-data">
<input type="hidden" name="name" value="YOUR VALUE HERE">
<input type="hidden" name="email" value="YOUR VALUE HERE">
<input type="hidden" name="phone" value="YOUR VALUE HERE">
<input type="hidden" name="phone_ext" value="YOUR VALUE HERE">
<input type="hidden" name="topicId" value="NUMBER OF THE ROW RELATED TO THE HELP TOPIC" />
<input type="hidden" name="subject" value="INSERT YOUR VALUE HERE" />
<input type="hidden" name="message" value="THIS IS WHERE I WOULD INSERT THE URL" />
<p>
<input class="button" type="submit" name="submit_x" value="Submit Ticket">
</p>
</form>