I try load new module when previous one has been unloaded. So I let the moduler load module in the unload event handler. But the module can't be loaded ? moduler.unloadModule(); // actually it has not been unload moduler.loadModule(...); // the new one load moduler.unloadModule(); // When It has been unloaded modulerUnloadedHandler(e:ModuleEvent):void{ moduler.loadModule(...); // the new one load // but the new one can't load with no error ~~~ }