Flash Builder 4 Security Access Error Destination URL: DefaultHTTP

Question

Flash Builder 4 Security Access Error Destination URL: DefaultHTTP

I created an FB4 application that accesses the .NET web service of a partner company. The application works fine in the FB4 development environment, but will not work when published on my server. I can’t figure out how to get past the following error: URL Access Security Error Purpose: DefaultHTTP

It is unlikely that I will get the crossdomain.xml file on my server, so I'm trying to get it to work using a proxy. The .php proxy is in the same directory as swf, and works fine if I use it directly in the browser.

Below is what I have installed:

proxy.php:

<?php
$session = curl_init(trim(urldecode($_GET['url'])));                   // Open the Curl session
curl_setopt($session, CURLOPT_HEADER, false);          // Don't return HTTP headers
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);   // Do return the contents of the call
$xml = curl_exec($session);                            // Make the call
header("Content-Type: text/xml");                  // Set the content type appropriately
echo $xml;        // Spit out the xml
curl_close($session); ?>