Firefox 3.6.8 won't load Yahoo attachment uploader in Yahoo Mail

Yahoo mail has an attachment uploader that allows you to select multiple files (or pictures) for attachment. When installed, the link for attaching in a new message windos says "attach ". When not installed, the link says "Attach files more easily ". I have the attachment loader installed, but the link still says "Attach files more easily" in Firefox 3.6.8! I've tried re-installing the attachment uploader over and over, but when it tries to load it, it still ends up indicating that it's not installed ( "Attach files more easily "). I tried it in Internet Explorer and it works, but not in Firefox 3.6.8

I went and removed Firefox 3.6.8 and installed Firefox 3.5.7 and the attachment uploader works. 3.6.8 seems to have a bug that won't let me load and use the attachment uploader!

 

It is easy to say that the most recent version has a bug when an external program does not work. I am unfamiliar with this uploader, but it seems to me that it is an addon.
Addons must be compatible with Firefox, not the other way around.
A Search gave me several hits, but no help in figuring this out. The important thing is to see if you have this Attachment uploader in your Addon list or where, in 3.6.7.
And, I guess you are talking about Webmail.