I had the same problem. Check to see if you have any Windows OneCare programs installed. I had 2. After I uninstalled them, rebooted, everything worked fine. Make sure you install the printer locally before installing shareport. See http://social.microsoft.com/Forums/en-US/onecarefirewall/thread/5c584426-1fd2-4fe3-a7e1-7917ea1f3d92/ for more details.