How can I get this Php comment script to work?

So I've used a script and changed it to suit my needs. The reason it doesn't work, I think, is because I'm using two tables in a database. I've got one table for user info, and then im storing comments into another database and trying to combine the two. I've got my user info in a hidden input field and I want them to be posted next to the users comment, could somebody rewrite it for me?

<?php

if(isset($_POST['commentonit'])) {


$comment_on = $_POST['comment_on'];
$comment = $_POST['comment'];
$com_query = mysql_query("INSERT INTO com_system (comment_on, comment) VALUES ('$comment_on','$comment')");

if($com_query) {

$referance = $_SERVER['HTTP_REFERER'];
echo "Comment Inserted";
header("location: $referance");

}

else {

echo $commentfailure_msg;

}

mysql_close();

}

include($_SERVER["DOCUMENT_ROOT"]."/community/herotozero/database.php");

$name = $_SESSION['username'];
$query = "SELECT * from community WHERE name='$name'";
$result = mysql_query($query);
$row = mysql_fetch_assoc($result);

$name = $row['name'];
$email = $row['email'];
$entity = $row['entity'];
$city = $row['city'];
$country = $row['country'];
$website = $row['website'];
$facebook = $row['facebook'];
$twitter = $row['twitter'];
$deviantart = $row['deviantart'];

?>
<form action="" method="post">
<input type="hidden" autocomplete="on" class="required alphaspace" minlength="5" maxlength="49" id="name" name="name" readonly="readonly" value="<?=$name?>"/>
<input type="hidden" name="entity" autocomplete="on" id="entity" readonly="readonly" value="<?=$entity?>"/>
<input type="hidden" autocomplete="on" class="required alphaspace" minlength="2" maxlength="58" id="city" name="city" readonly="readonly" value="<?=$city?>"/>
<input type="hidden" autocomplete="on" class="required alphaspace" minlength="2" maxlength="38" id="country" name="country" readonly="readonly" value="<?=$country?>"/>
<input type="hidden" autocomplete="on" class="url" minlength="15" maxlength="70" id="website" name="website" readonly="readonly" value="<?=$website?>"/>
<input type="hidden" autocomplete="on" class="url" minlength="15" maxlength="58" id="facebook" name="facebook" readonly="readonly" value="<?=$facebook?>"/>
<input type="hidden" autocomplete="on" class="url" minlength="14" maxlength="57" id="twitter" name="twitter" readonly="readonly" value="<?=$twitter?>"/>
<input type="hidden" autocomplete="on" class="url" minlength="24" maxlength="67" id="deviantart" name="deviantart" readonly="readonly" value="<?=$deviantart?>"/>
<input type="hidden" name="comment_on" readonly="readonly" value="<?php echo md5($_SERVER['PHP_SELF']);?>"/>
<textarea name="comment" minlength="30" maxlength="255" class="required alphaunct" id="comment">COMMENT SYSTEM IN CONSTRUCTION</textarea>
Leave A Comment<br/>
<input class="submit" type="submit" value="Post Comment" name="commentonit"/>
</form>
<?php

$webpage_name = md5($_SERVER['PHP_SELF']);
$com_query = mysql_query("SELECT * from com_system where comment_on='$webpage_name' ORDER BY id DESC LIMIT 0, $commentlimit");

echo "<h1>Latest Comments</h1>";
while($fetch = mysql_fetch_array($com_query)) {

echo "<p>".$fetch['comment']."<br/>_{<b>Name</b>".$fetch['name']."}<hr /><p>";

}

?>

 

is this script is from 1 page or combined ?

 

Yes, it's all on the same page, I only recently learned how to do this. I successfully did it with the login/registration rather than having a form page then the confirm page.