When launching the Tor browser from its folder it keeps on failing. The Connection Settings is set to Manual Proxy with SOCKS Host at 127.0.0.1 Port 9150 v5.
This is a known bug in Vidalia (soon to be replaced by Tor Launcher). When you modify some settings in Vidalia it writes an incorrect SocksPort in the torrc file (9050) which will break the proxy between Tor and Tor Browser (Proxy server is refusing connection).
You can fix this by navigating to your Tor browser folder then open Data/Tor/torrc with notepad then edit the following line:
SocksPort 9050 to SocksPort 9150
then save and restart Vidalia/Tor.
Or you can avoid all of this and use Tor Browser 3.0 beta-1.
I tried all these so-called fixes with the socksport 9050 to 9150 and none worked. What finally worked for me was completely uninstall Tor Browser and download and re-install Tor Browser. Do not re-install before un-installing first. I had been wrestling with this for a couple weeks off and on. Just do it.