Xml flash and php intro tutorial question

http://www.kirupa.com/php_xml/xml/examples/simpleeditor.htm

I am on this page, and I am trying to learn how to send the xml i have in flash to php and then from the php file to a file on the server. my php file is exactly like the one in the tutorial but it leaves the xml file on the server blank.

now, my XML does contain some html

when the blank window comes up when I used XML.send instead of sendAndLoad i get the: www.example.com?<xmlcontent html=blahblah>

the only part of teh php I don’t get is:
$raw_xml = file_get_contents(“php://input”);

any help with this would be great! thanks.