when validating a site using w3c validator it tells me the embed tag is not valid markup. So i take it out and it works on safari/chrome but not firefox(3.5.x) but validates fine. Is there something in the object tag i must add in order for firefox to display flash.
embed has never been part of the HTML spec and object should be used. It's been so long since I've touched flash, I hesitate to say more than that which I know.
You should use swfobject. It's valid, although I think I've had the validator trip up on it before (the w3 validator has been known to trip up on stuff like this on occasion).
A List Apart has a great article on that topic: Flash Satay: Embedding Flash While Supporting Standards.
Read that to understand the general difficulties with embedding flash and to read about different approaches to embed it in valid HTML. And then go and use SWFobject to embed Flash as that is the best way to do it while having both standards support and browser compiliance.
In addition to that you may use the normal Flash Satay method to embed it for people without JavaScript.