I have installed Vidalia and when I activate Tor and set the proxies in firefox I get the message '514 Authentication Required.'!
I'm wondering what is the problem here?
Usually this message comes when you entered a wrong port. Please check that you chose port 9050 in your Firefox settings. The 514 error code comes when you choose 9051. This port is called control port and works only with some form of authentication. However a better alternative is to use Polipo or Privoxy. If you also install them you have to choose port 8123 for Polipo and 8118 for Privoxy. After entering those data you should visit the check page. It will tell you if you are using Tor or not.