The swf of data browser application that you are loading is flash application or flex application?
if you trying to interact with the loaded application that was compiled by flash rather then flex then it will simply wont work.Because flash and flex applications cant coexist in same application domain.In order to make your dataBrowser application to work you need to wirte all that into a separate flex moudle then load it into your flex application using flex moduleLoader.
for more information on modules visit http://livedocs.adobe.com/flex/3/html/help.html?content=modular_1.html
It's a flex application, i thought about creating it as a module but i want the ability to use it on it's own as well as being called through other flex apps.
I've now converted the code into a module and it works as expected, no idea what the differences between moduleloader and swfloader are but somethings changed. Something to do with singletons maybe?