For security reasons, the Flash Player doesn't allow applications to access both the file system and the network.
One workaround is to compile the plugins in statically (rather than load them dynamically). The Akamai Plugin Sample shows you how to load plugins either way, you can see the source here: http://opensource.adobe.com/svn/opensource/osmf/trunk/apps/samples/plugins/AkamaiPluginSam ple/.
Yes, but FB makes bin-debug dir trusted, and swf from that dir can access any url: local or network. It works with any other swf, but why not with plugin swfs ?