Paolo, you must ensure that you have the latest release version of '
Weather Display'.
Then, in the directory where Weather Display has been installed, look for and click/start 'crondaviswll.exe' - on the bottom left of that 'Davis WLL' window, under the heading "IP Address", enter your the IP address of your WeatherLink Live unit. Clicking on the buttom left buttons should display information about the WeatherLink Live unit. Yo can eventually close down that window.
Weather Display must also be setup to use the WeatherLink Live unit for its data.