I don't think you can use that declaration for time_sunset. For my Advanced Smart Lights code, I use a different approach.
time_sunrise = DateTime.ParseExact(Program.WithName("jkUtils - Solar Altitude").Parameter("jkUtils.SolarAltitude.Morning.Sunrise.Start").Value, "H:mm", System.Globalization.CultureInfo.InvariantCulture);
time_sunset = DateTime.ParseExact(Program.WithName("jkUtils - Solar Altitude").Parameter("jkUtils.SolarAltitude.Evening.Sunset.End").Value, "H:mm", System.Globalization.CultureInfo.InvariantCulture);
The important part is that I use ".Parameter("jkUtils.SolarAltitude.Morning.Sunrise.Start").Value". You might be able to use your "@SolarTimes.Sunrise" assignment, but I think you will need to use quotes at a minimum.