onClipEvent ? in externally loaded .swf

I have this action on a form_mc for an email.swf

onClipEvent(data){
_root.nextFrame();
}

It works fine when I test it but when I load in my main_content movie it doesn’t do anything. I just need it to show the next frame for the ‘Thank You’ screen and thats the end of that .swf.

Thanks