Tor Security Firefox Plug in

I downloaded/ran the Torbutton application which is supposed to help act as a proxy to ensure privacy (as I heard it was good). (https://addons.mozilla.org/en-US/firefox/addon/2275/)

But when it is enabled I get the below message when I try and open a page. Can anyone help me get to the bottom of why this is happening? Is it as simple as it appears?
I am using the latest version of Firefox in Xp sp2 with comodo.
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The proxy server is refusing connections



Firefox is configured to use a proxy server that is refusing connections.



* Check the proxy settings to make sure that they are correct.

* Contact your network administrator to make sure the proxy server is
working.




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Not entirely sure how to check the proxy settings to make sure they are correct.... But looking at the Torbutton options the proxy settings are on 'recommended...' .