Your firefox is out of date if you get errors like below:
Secure Connection Failed
An error occurred during a connection to www.torproject.org.
Unable to generate public/private key pair.
(Error code: sec_error_keygen_fail)
* The page you are trying to view can not be shown because the authenticity of the received data could not be verified.
* Please contact the web site owners to inform them of this problem. Alternatively, use the command found in the help menu to report this broken site.