The swf tag should work within firefox 2.x. Were you saying that it was working on 2.x before but not now? Could you please make sure that your operating system is on the list of A grade browsers / OS supported by Yahoo! http://developer.yahoo.com/yui/articles/gbs/. If it is we'll set up some tests to see if there is a problem with the last firefox 2.x release.
Jonathan LeBlanc Senior Software Engineer Yahoo! Developer Network