when you add a flash file to joomla,the Flash is not working/displaying,why?
flash player has a built is security sandbox that only allows php scripts to be called from an exact dmain name match. thi smeans, if you joomla/mambo config live site parameter is missing the 'www.' the flash will not work right. there is a fix, direct from Macromedia it is called crossdomain.xml <?xml version="1.0"?>

<!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-access-from domain="*" />
</cross-domain-policy>
copy/paste this blue text into a plain textfile, then rename it to: crossdomain.xml upload this (FTP, SSH etc) to your mambo/Joomal root directory.