Does anyone know anything about this?
Hello Hazar,
Have you seen Mozilla's page on accessibility?
http://www.mozilla.org/access/
I think your question may be best answered at  
mozilla.dev.accessibility (for developers) or  
mozilla.support.accessibility (for end-users.)
https://lists.mozilla.org/listinfo/dev-accessibility
or
http://groups.google.com/group/mozilla.dev.accessibility/topics
and
https://lists.mozilla.org/listinfo/support-accessibility
or
http://groups.google.com/group/mozilla.support.accessibility
Firefox 3 is now using the open source graphics library Cairo to do  
new rendering of text and graphics.  This change may be part of the  
problem if Babylon Translator has not been updated to support Firefox 3.
Please look to the Mozilla accessibility community for more specific  
information on Babylon Translate.
Sincerely,
Gen Kanai
You can use Lingoes ( http://www.lingoes.net/ ) that now works well
with Firefox 3 and it's free.