Hi, I'm not that familiar with FM4 but what version of OSMF is is expecting? Apache Flex uses 1.0 and it may be that your code is expecting a later version and need to use a newer version of osmf.swf.
It looks like that class isn't in the current version of OSMF we use. Running this: ./swfdump ../frameworks/libs/osmf.swc | grep "MulticastResource" Finds nothing. This has been open for some time: https://issues.apache.org/jira/browse/FLEX-33119 Thanks, Justin
