SERVER['PHP_SELF'] Breaking snippet?

<?php

// ++++++++++++++++++++++++++++ 
// part 1 :: propegate drop down box...
// ++++++++++++++++++++++++++++

$u = $modx->getFullTableName("web_user_attributes"); 
$w = $modx->getFullTableName("web_groups"); 
$n = $modx->getFullTableName("webgroup_names"); 

// Begin query
$sql ="SELECT DISTINCT n.id, n.name FROM {$n} n LEFT JOIN {$w} w ON n.id = w.webgroup LEFT JOIN {$u} u ON u.id = w.webuser"; 

// Check optional paramaters  
if (isset($type) )
{
$sql .=" WHERE u.type = '{$type}'";
}

if (isset($remodeler) )
{
$sql .=" WHERE u.remodeler = '{$remodeler}'";
}

// execute query
$sql .=" ORDER BY n.name ASC";
$categories = $modx->db->query($sql);

if ($categories) {
	echo '<form name="dd" id="dd" method="POST" action='.$_SERVER['PHP_SELF'].'>';
	echo '<input type="radio" name="ddType" value="1">Builders</input>';
	echo '<input type="radio" name="ddType" value="2">Associates</input><br />';
	echo '<select name="ddCat" onchange="document.dd.submit()" id="ddCat">';
		echo '<option selected value="Select a category.">Select a category.</option>';
		while ($row = mysql_fetch_array($categories) ) {
        	echo '<option value="'.$row{'id'}.'">'.$row{'name'}.'</option>';
	    }
			echo '</select>';
			echo '</form>';
		} else {
			echo 'There are no categories to display.';
		
} 

// ++++++++++++++++++++++++++++ 
// part 2 :: display results
// ++++++++++++++++++++++++++++

$ddType = $_POST['ddType'];
$ddCat = $_POST['ddCat'];
$ddFields = 'u.company, u.website, u.comment, u.address, u.city, u.state, u.zip, u.fullname,u.phone, u.fax, u.mobilephone, u.email';

$sql2 = "SELECT {$ddFields} FROM {$u} AS u
JOIN {$w} AS w ON u.id = w.webuser
WHERE u.type = '{$ddType}'
AND w.webgroup = '{$ddCat}' 
ORDER BY u.company ASC";	

if (isset($ddCat) ) {
	$output = 'User selected -> '. $ddCat . '.';
	
	$members = $modx->db->query($sql2);

	if ($members) {
		$output .= '<table>';	
		$output .= '<tr><td><strong>Results</strong>';
		while ($row = $modx->db->getRow($members)) {
		$output .= '<tr><td>' . $row{'company'} . '</td></tr>';
		}
		$output .= '</table>';
	}
}
return $output;
?>

<?php
    echo '<form name="dd" id="dd" method="POST" action='.$_SERVER['PHP_SELF'].'>';
?>

<?php
    echo '<form name="dd" id="dd" method="GET" action='.$_SERVER['REQUEST_URI'].'>';
?>

<?php
    $ddType = $_POST['ddType'];
    $ddCat = $_POST['ddCat'];
?>