Fatal error: Call to undefined function: xmldoc()

Hi,

I am working with a Flash application where I load a .XML file from an apache server into my flash app. Now I would like to send the file from flash to the server and have the server save the file to the hard drive. I have a great example from ActionScript 3.0 Cookbook but there is a PHP mode that is not working with my server.

Can someone please help me solve this php problem?

Here is the PHP code and error I am receiving.

<?php
     
// Read In XML from Raw Post Data.
$xml = $GLOBALS['HTTP_RAW_POST_DATA'];
     
// Process XML using DOM PHP extension.
$document = xmldoc($xml);
     
// Read root element <gameinfo>.
$rootElement = $document->root(  );
     
// Read child nodes <username> and <score>.
$childNodes = $rootElement->children(  );
     
$data = "";
     
// Loop through child nodes and place in array.
foreach($childNodes as $childNode){
  // Add data to array;
  $name = $childNode->tagName(  );
  $value = $childNode->get_content(  );
  $data[$name] = $value;
}
     
// Append data to scores.txt ( format: username|score )
$fp = fopen("scores.txt","a+");
$dataString = $data['username'] . "|" . $data['score'] . "\n";
fputs($fp,$dataString,strlen($dataString));
fclose($fp);
     
// Return success code to Flash
echo "<success>1</success>";
?>

The error from the browser:
Fatal error: Call to undefined function: xmldoc() in ...

I have looked this error up in google and I have tried a few things but nothing works.

The server is Ubuntu with apache 1.3 and php4.4.0

waffe