known windows firewall issue
 

If you load a new version of Vizard onto a computer (when putting R3 on a computer that has R2 running on it), it changes the name of winviz on the old version so that Windows firewall sometimes doesn't recognize it. To fix it, simply set the windows firewall permissions correctly again - usually there is a window coming up that asks you if you allow the winviz file to execute, and you need to click on YES.