help with my php code

[wilsonshen]

Hi,
Recently I am try to do some programming work.
I want my Zen Cart store to update tracking information to the online system of our shipping agency.
I got strange problem.
I installed in my local PC:
Apache 2.2.9
PHP 5.2.6
MySQL 5.1.28＆4.0.26

I also install a zencart in my local PC.
I ran the following track.php file in my PC:

<?php
echo "hi";
var_dump(esp_track_result('10465708'));

function esp_track_result($sn){
$url         = "http://api.espeedpost.com/track/";
$devid     = "EspeedPost";
$appid     = "80010616-XXXXXXXXXXXX";
if ($sn != '')
    {
    $string = array
    (
    "devid" => $devid,
    "appid" => $appid,
    "cus_name" => "no",
    "cus_value" => $sn,
    );

    $content = Post($url, $string);  
    
    
    
    $objXmlToArray=new xmlToArray();
    $objXmlToArray->parseString($content);
    $data = $objXmlToArray->getTree();
    //print_r($data);
    $objXmlToArray->free();

    //提取查询信息
    $result = $data[GetTrackingInformation][Result][value];

    if ($result == "Success"){
    //echo "The latest status of parcel ".$data[GetTrackingInformation][ParcelNumber][value]." is ".$data[GetTrackingInformation][ParcelInfo][LastStatusContent][value]." at ".$data[GetTrackingInformation][ParcelInfo][LastDateTime][value]."\n";
    //echo "AAAAAA";
    return $data[GetTrackingInformation][ParcelNumber][value];
    }
    if ($result == "Failure"){
    //echo $data[GetTrackingInformation][Reason][value]."\n";
    //echo "BBBBBBB";
    return false;
    }
    
    
    }

}
////////////////////////////////////////////////////////

///////////////////////////////////////////////////////
function Post($url, $post = null)
{  
$context = array();  
  
if (is_array($post))    
    {  
    ksort($post);  
    $context["http"] = array
        (  
        "method" => "POST",  
        "content" => http_build_query($post, "", "&"),  
        );  
    }  
    return file_get_contents($url, false, stream_context_create($context));  
}

//////////////////////////////////////////////////////
function urlvalue($urlname)
{
$urlvalue = !empty($_POST[$urlname]) ? $_POST[$urlname] : $_GET[$urlname];
return $urlvalue;
}

//////////////////////////////////////////////////////////
class xmlToArray
{
    var $parser;
   
    /**
    * source encoding
    *
    * @var string
    */
    var $srcenc;
   
    /**
    * target encoding
    *
    * @var string
    */
    var $dstenc;
   
    /**
    * the original struct
    *
    * @access private
    * @var array
    */
    var $_struct = array();
   
    /**
    * Constructor
    *
    * @access public
    * @param mixed [$srcenc] source encoding
    * @param mixed [$dstenc] target encoding
    * @return void
    * @since
    */
    function xmlToArray($srcenc = null, $dstenc = null)
    {
        $this->srcenc = $srcenc;
        $this->dstenc = $dstenc;
       
        // initialize the variable.
        $this->parser = null;
        $this->_struct = array();
    }
   
    /**
    * 释放资源
    *
    * @access public
    * @return void
    **/
    function free()
    {
        if (isset($this->parser) && is_resource($this->parser))
        {
            xml_parser_free($this->parser);
            unset($this->parser);
        }
    }
   
    /**
    * 解析XML文件
    *
    * @access public
    * @param string [$file] the XML file name
    * @return void
    * @since
    */
    function parseFile($file)
    {
        $data = @file_get_contents($file) or die("Can't open file $file for reading!");
        $this->parseString($data);
    }
   
    /**
    * 解析XML字符串
    *
    * @access public
    * @param string [$data] XML data
    * @return void
    */
    function parseString($data)
    {
        if ($this->srcenc === null)
        {
            $this->parser = @xml_parser_create() or die('Unable to create XML parser resource.');
        }
        else
        {
            $this->parser = @xml_parser_create($this->srcenc) or die('Unable to create XML parser resource with '. $this->srcenc .' encoding.');
        }
       
        if ($this->dstenc !== null)
        {
            @xml_parser_set_option($this->parser, XML_OPTION_TARGET_ENCODING, $this->dstenc) or die('Invalid target encoding');
        }
        xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING, 0); // lowercase tags
        xml_parser_set_option($this->parser, XML_OPTION_SKIP_WHITE, 1); // skip empty tags
        if (!xml_parse_into_struct($this->parser, $data, &$this->_struct))
        {
            printf("XML error: %s at line %d",
            xml_error_string(xml_get_error_code($this->parser)),
            xml_get_current_line_number($this->parser)
        );
        $this->free();
        exit();
        }
       
        $this->_count = count($this->_struct);
        $this->free();
    }
   
    /**
    * 返回解析完毕后的XML数组
    *
    * @access public
    * @return array
    */
    function getTree()
    {
        $i = 0;
        $tree = array();
       
        $tree = $this->addNode(
            $tree,
            $this->_struct[$i]['tag'],
            (isset($this->_struct[$i]['value'])) ? $this->_struct[$i]['value'] : '',
            (isset($this->_struct[$i]['attributes'])) ? $this->_struct[$i]['attributes'] : '',
            $this->getChild($i)
        );
       
        unset($this->_struct);
    return ($tree);
    }
   
    /**
    * recursion the children node data
    *
    * @access public
    * @param integer [$i] the last struct index
    * @return array
    */
    function getChild(&$i)
    {
    // contain node data
    $children = array();
   
    // loop
    while (++$i < $this->_count)
    {
    // node tag name
    $tagname = $this->_struct[$i]['tag'];
    $value = isset($this->_struct[$i]['value']) ? $this->_struct[$i]['value'] : '';
    $attributes = isset($this->_struct[$i]['attributes']) ? $this->_struct[$i]['attributes'] : '';
   
    switch ($this->_struct[$i]['type']) {
    case 'open':
    // node has more children
    $child = $this->getChild($i);
    // append the children data to the current node
    $children = $this->addNode($children, $tagname, $value, $attributes, $child);
    break;
    case 'complete':
    // at end of current branch
    $children = $this->addNode($children, $tagname, $value, $attributes);
    break;
    case 'cdata':
    // node has CDATA after one of it's children
    $children['value'] .= $value;
    break;
    case 'close':
    // end of node, return collected data
    return $children;
    break;
    }
   
    }
    //return $children;
    }
   
        /**
        * Appends some values to an array
        *
        * @access public
        * @param array [$target]
        * @param string [$key]
        * @param string [$value]
        * @param array [$attributes]
        * @param array [$inner] the children
        * @return void
        * @since
        */
        function addNode($target, $key, $value = '', $attributes = '', $child = '')
        {
            if (!isset($target[$key]['value']) && !isset($target[$key][0]))
            {
                if ($child != '')
                {
                    $target[$key] = $child;
                }
                if ($attributes != '')
                {
                    foreach ($attributes as $k => $v)
                    {
                    $target[$key][$k] = $v;
                    }
                }
           
                $target[$key]['value'] = $value;
            }
            else
            {
                if (!isset($target[$key][0]))
                {
                    // is string or other
                    $oldvalue = $target[$key];
                    $target[$key] = array();
                    $target[$key][0] = $oldvalue;
                    $index = 1;
                }
                else
                {
                    // is array
                    $index = count($target[$key]);
                }
           
                if ($child != '') {
                $target[$key][$index] = $child;
                }
           
                if ($attributes != '') {
                foreach ($attributes as $k => $v) {
                $target[$key][$index][$k] = $v;
                }
                }
                $target[$key][$index]['value'] = $value;
            }
            return $target;
        }
}

//////////////////////////////////////////////////////////////////////
?>

Everything works fine. I could get reply.
However, I upload the code to my server:
Apache version 2.2.26
PHP version 5.2.17
MySQL version 5.5.36-log

The php could not run. I got nothing on my browser. Even the first code replying "hi" seems not work. Nothing replied even error indication.
I also wrote other php files and they all could run.
Any ideal what 's wrong?
Thanks for your time.