First error, when you try to run InitAllApplications.xaml is because the in_Config argument is not set (it is Nothing or null) and you try to get a value from it - in_Config(“UiDemoPath”).ToString. This is the part that throws that “Object reference…” error. To fix this, to run only this workflow, you should create a unit test. Create a new workflow named InitAllApplications_Test.xaml and invoke there InitAllSettings.xaml and then InitAllApplications.xaml. Map the arguments as necessary (check how InitAllSettings.xaml is invoked in Init). Then you’ll get the Config dictionary that can be used as input argument for InitAllApplications.
Second error, when you try to run main is because your Config.xlsx file does not contains a column “Value” or because the Read Range in InitAllSettings.xaml does not have the “Add Headers” checked.
Please check both cases and let us know if problem is fixed or not.