Security Sandbox Violation: Lack of Policy File Permissions

I'm using as3httpclientlib to post data to my web service, but I'm continually
getting the following security violation. Does anyone know how to resolve this?
My crossdomain.xml file is below the security violation notice.

NOTE: I'm using apache to proxy requests to the web service, therefore the target url/port and the url/port serving the applet are the same — i.e. http://192.168.100.101. Also, the crossdomain.xml file is located in the root of the web app which serves the applet rather the web service; however, since the requests are proxied the url for the file is http://192.168.100.101/crossdomain.xml

* Security Sandbox Violation * Connection to 192.168.100.101:80
halted – not permitted from
http://192.168.100.101/com-web/flex/ComUi.swf Error: Request for resource at
xmlsocket://192.168.100.101:80 by
requestor from
http://192.168.100.101/com-web/flex/ComUi.swf
is denied due to lack of policy file
permissions.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE cross-domain-policy SYSTEM
"http://www.adobe.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-http-request-headers-from domain="*" headers="*" secure="false" />
<allow-access-from domain="*" to-ports="80, 8080" />
</cross-domain-policy>

Thanks.