Try this
<h2>Please fill in the form below to open a new ticket.</h2>
<form action="http://OSTICKETROOT/open.php" method="post" enctype="multipart/form-data">
<fieldset id="form-name" class="Required">
<label>Full Name:</label>
<input type="text" name="name" value="CLIENT SPECIFIC" />
<BR>
</fieldset>
<fieldset id="form-email" class="Required">
<label>Email Address:</label>
<input type="text" name="email" value="CLIENT SPECIFIC" />
<BR>
</fieldset>
<fieldset >
<label>Telephone:</label>
<input type="text" name="phone" value="CLIENT SPECIFIC" />
</fieldset>
<fieldset id="form-topic" class="Required">
<label>Help Topic:</label>
<select name="topicId">
<option value="" >Select One</option>
<BR>
<option value="0" >General Inquiry</option>
<option value="1" >Billing</option>
<option value="2" >Support</option>
</select>
</fieldset>
<fieldset id="form-subject" class="Required">
<label>Subject:</label>
<input type="text" name="subject" value="" />
</fieldset>
<fieldset id="form-message" class="Required">
<label>Message:</label>
<textarea rows="5" cols="80" name="message"></textarea>
</fieldset>
<?}?>
<fieldset id="button-group">
<input class="FormButton" type="submit" name="submit_x" value="Submit Ticket" />
<input class="FormButton" type="reset" value="Reset" />
<input class="FormButton" type="button" name="cancel" value="Cancel" onclick='window.location.href="index.php"' />
</fieldset>
</form>
Thats the html integration to whatever page. Note: the many field sets might fight some CSS, but that's secondary here.
Also, note the form action, since it is outside of the osTicket installation, (or rather will be on some other site) NEEDS to be written as a direct http://blahblahblah.com(http://blahblahblah.com), no relative links will work.
Next, Line 29 of open.php
$inc='thankyou.inc.php';
Change 'thankyou.inc.php' to where you want your users to be redirected to. Remember, same as before you MUST use http://blah(http://blah) blah, relative links will NOT work.
Hope it helps.