We got a report that Planner.NET crashes when Windows regional settings are set to Italian. We've tracked the problem to the ColorConverter trying to parse color values in (R;G;B) format, while the themes colors are saved in (R,G,B) format in the resources. We are going to release a patch for that in a couple of days; until then do not ship your applications using current Planner.NET 1.2 version if they will be used in international markets.