Originally Posted by
cshha
The parameter variable is null, meaning that the parameter was not found on that element. I see that the parameter name in the shared parameter file you posted is actually "ProjectNo" and not "myProjectNo". Make sure you've spelled the parameter name correctly - the name is also case sensitive so keep that in mind as well.
If you want to explore an element's parameters, you should use RevitLookup which is part of the SDK. I don't think it comes pre-built so you'll need to compile it in Visual Studio and add the add-in to Revit yourself. It comes with instructions on how to do this.