I have a html file that sends POST information to another php file, but the php file wont return XML
HTML Code:
<HTML> <head> 
        <script type="text/javascript">
        <!--
            function createRequestObject() 
            {
                var ro;
                if (navigator.userAgent.search(/MSIE/) >= 0) 
                {
                    ro = new ActiveXObject("Microsoft.XMLHTTP");
                }
                else
                {
                    ro = new XMLHttpRequest();
                }
                return ro;
            }

            var request = createRequestObject();
            
            function reverseMd5(md5)
            {
                if (md5.length > 0)
                {
                    request.open('get', 'md5.php?hash=' + escape(md5));
                    request.onreadystatechange = handleReverseMd5;
                    request.send(null);
                }
            }
            function handleReverseMd5() 
            {
                if (request.readyState == 4) // Finished
                {
                    var response = request.responseXML;
                    var root     = response.documentElement;
                    var hash     = root.getElementsByTagName('hash');
                    var string   = root.getElementsByTagName('string');
                    var error    = root.getElementsByTagName('error');
                    var returnString;
                    
                    if (hash.length)   { hash = hash[0].firstChild.data; }
                    if (string.length) { string = string[0].firstChild.data; }
                    if (error.length)  { error = error[0].firstChild.data; }

                    if (error.length > 0)
                    {
                        returnString  = '<p class="error">';
                        returnString += error;
                        returnString += '<\/p>';
                    }
                    else 
                    {
                        returnString  = '<p>The given MD5 hash reverses to:<\/p>';
                        returnString += '<p class="result">' + string + '<\/p>';
                    }

                    document.getElementById('return').innerHTML = returnString;
                }
                else if (request.readyState == 1) // Loading
                {
                    document.getElementById('return').innerHTML = '<p class="status">Loading from server . . .<\/p>';
                }
            }

            function getMd5(str)
            {
                if (str.length > 0)
                {
                    var md5 = hex_md5(str);
                    document.getElementById('md5').value = md5;
                    reverseMd5(md5);
                }
            }

            function disableReturnKey(evt) 
            {
                var evt  = (evt) ? evt : ((event) ? event : null);
                var node = (evt.target) ? evt.target : ((evt.srcElement) ? evt.srcElement : null);
                if ((evt.keyCode == 13) && (node.type=="text")) { return false; }
            }
            document.onkeypress = disableReturnKey;
        // -->
        </script>
    </head>
    <body>
        <p>This form uses several MD5 databases to look up an MD5 hash and 
            return its original counterpart. You may use the second field to 
            first generate an MD5 hash of a string to use in a reverse 
            lookup.</p>
        <div id="results">
            <h2>Results</h2>
            <div id="return"><p>The results of the reversed hash will be displayed here.</p></div>
        </div>
        <div id="form-area">
            <form id="md5form" method="post" action="phpinfo.php">
                <p>
                    <label for="md5">Hash to reverse:</label><br />
                    <input type="text" name="md5" id="md5" onblur="reverseMd5(document.getElementById('md5').value);" />
                    <input type="button" name="reverse" id="reverse" value="Reverse Hash" onclick="reverseMd5(document.getElementById('md5').value);" />
                </p>

                <p>
                    <label for="string">String to convert to an MD5 hash:</label><br />
                    <textarea name="string" id="string" rows="10" cols="50" onblur="getMd5(document.getElementById('string').value);"></textarea><br />
                    <input type="button" name="create" id="create" value="Create MD5 Hash" onclick="getMd5(document.getElementById('string').value);" />
                </p>
                <p><input type="reset" value="Clear Form" onclick="document.getElementById('return').innerHTML = '<p>The results of the reversed hash will be displayed here.</p>';" /></p>
            </form>
        </div>
        <hr />
    </body>
</html>
phpinfo.php
PHP Code:
<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

require_once 'HTTP/Request.php';

/* MD5 databases we're using; corresponds to a function name */
$md5_stores = array(
    'rednoize',   // md5.rednoize.com
    'schwett',    // www.schwett.com
    'crysm_us',   // us.md5.crysm.net
    'crysm_nz',   // nz.md5.crysm.net
    'gdata'       // gdataonline.com
);

/* Provides escaping for output to XML */
function escape_xml($input)
{
    $output  = '<![CDATA[';
    $output .= $input;
    $output .= ']]>';
    
    return $output;
}

/* md5.rednoize.com */
function md5_rednoize($str)
{
    $xml = simplexml_load_file("http://md5.rednoize.com/?q={$str}&xml");

    $string = (string) $xml->ResultString;

    if (strlen($string) > 0)
    {
        return $string;
    }
}

/* www.schwett.com */
function md5_schwett($str)
{
    $xml = simplexml_load_file("http://www.schwett.com/md5/xml.php?hash={$str}");

    $string = (string) $xml->password->cleantext;

    if (strlen($string) > 0)
    {
        return $string;
    }
}

/* us.md5.crysm.net */
function md5_crysm_us($str)
{
    $data = '';
    $req =& new HTTP_Request("http://us.md5.crysm.net/find?md5={$str}");
    
    if (!PEAR::isError($req->sendRequest())) 
    {
        $data = $req->getResponseBody();
    }

    if (preg_match('!<li>(.*?)</li>!', $data, $m)) 
    {
        return $m[1];
    }
}

/* nz.md5.crysm.net */
function md5_crysm_nz($str)
{
    $data = '';
    $req =& new HTTP_Request("http://nz.md5.crysm.net/find?md5={$str}");
    
    if (!PEAR::isError($req->sendRequest())) 
    {
        $data = $req->getResponseBody();
    }

    if (preg_match('!<li>(.*?)</li>!', $data, $m)) 
    {
        return $m[1];
    }
}

/* gdataonline.com */
function md5_gdata($str)
{
    $data = '';

    if (!empty($_SERVER['HTTP_USER_AGENT'])) 
    {
        $ua = strtr($_SERVER['HTTP_USER_AGENT'], "\r\n", '  '); /* CRLF protection */
    } 
    else 
    {
        $ua = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4';
    }

    $req =& new HTTP_Request('http://gdataonline.com/seekhash.php');
    $req->setMethod(HTTP_REQUEST_METHOD_POST);
    $req->addHeader('User-Agent', $ua);
    $req->addHeader('Referer', 'http://gdataonline.com/seekhash.php');
    $req->addPostData('hash', $str);
    
    if (!PEAR::isError($req->sendRequest())) 
    {
        $data = $req->getResponseBody();
    }

    if (preg_match('!<td width="35%"><b>(.*?)</b></td>!', $data, $m)) 
    {
        return trim($m[1], '?');
    }
}


/* Start processing the request */
$clean = array();
$url   = array();
$xml   = array();

/* Ensure the hash is exactly 32 alpha-numeric characters */
if (strlen($_GET['hash']) == 32 && ctype_alnum($_GET['hash']))
{
    $clean['hash'] = $_GET['hash'];
}
else
{
    $xml['error'] = escape_xml('The string provided is not a true MD5 hash. Please try again.');
}

/* Perform the MD5 hash lookup */
if (isset($clean['hash']))
{
    $url['hash'] = urlencode($clean['hash']);
    
    $string = NULL;

    /* Iterate through the MD5 stores to find a value for the hash */
    foreach ($md5_stores as $store)
    {
        $f = "md5_{$store}";
        if (($string = $f($url['hash'])))
        {
            break;
        }
    }

    if (strlen($string) > 0 && ctype_print($string))
    {
        $clean['string'] = $string;
    }
    else
    {
        $xml['error'] = escape_xml('No value in MD5 database for this hash.');
    }
}

/* Prepare data for output */
if (isset($clean['hash']))
{
    $xml['hash'] = escape_xml($clean['hash']);
}

if (isset($clean['string']))
{
    $xml['string'] = escape_xml($clean['string']);
}

/* Set content type to text/xml for output */
header('Content-type: text/xml');
echo '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
?>
<md5lookup>
<?php if (isset($xml['error'])): ?>
    <error><?php echo $xml['error']; ?></error>
<?php else: ?>
    <hash><?php echo $xml['hash']; ?></hash>
    <string><?php echo $xml['string']; ?></string>
<?php endif; ?>
</md5lookup>

thanks in advance for anyone that can help.