The Windows Firewall/Internet Connection Sharing service is enabled for %s. Click Start, click Administrative Tools, click ...

The Windows Firewall/Internet Connection Sharing service is enabled for %s.  Click Start, click Administrative Tools, click Services, and search for the Windows Firewall/Internet Connection Sharing service.  Make sure that the status for this service is Stopped and that the startup type is Disabled, and then try again.

You must be an administrator in order to complete these steps.