Flash security constraints can prevent a SWF hosted on one domain from reading data hosted on another domain. Users trying out the SlideSync and SlideScroller plugins might encounter this issue if the XML data file that contains the slide URLs and timing is on a different website from the one that hosts the JW FLV Player itself.
The solution is to add a crossdomain.xml file to the root directory of the web server that hosts the XML file. There’s official Adobe docs on crossdomain policy files, and here’s a pretty good tutorial on crossdomain.xml files.
In short, you create this simple file using any text editor, and set up a rule describing which other sites may access data hosted on the site where the crossdomain.xml file lives.
<!DOCTYPE cross-domain-policy SYSTEM "http://www.adobe.com/xml/dtds/cross-domain-policy.dtd">
<allow-access-from domain="*.learningapi.com" />