On debugging the following code I have an exeption on load method (shown bold)

string templateFileName = @"C:\Documents and Settings\All Users\Application Data\Autodesk\RVT 2014\Family Templates\Russian\Метрическая система, типовая модель.rft";

Document familyPlate = externalCommandData.Application.Application.NewFamilyDocument(templateFileName);

Transaction transaction = new Transaction(familyPlate, "pop");

transaction.Start();

familyPlate.OwnerFamily.Name = "Plate";

familyPlate.FamilyManager.NewType("Plate Type 1");

transaction.Commit();

familyPlate.SaveAs(@"D:\Arhive\Visual Studio\HelloWorld\1.rfa");

Document familyBlock = externalCommandData.Application.Application.NewFamilyDocument(templateFileName);

Transaction transaction2 = new Transaction(familyBlock, "pop2");

transaction2.Start();

familyBlock.LoadFamily(familyPlate);

transaction2.Commit();

familyBlock.SaveAs(@"D:\Arhive\Visual Studio\HelloWorld\2.rfa");

return Autodesk.Revit.UI.Result.Succeeded;