AutoCAD .NET :: Writing Tool To Add Custom Drawing Properties

I have installed the autocad ObjectARX 2011 and .Net wizzard to start writing a .Net application for adding custom drawing parameters to all our acad drawings.  I have found two issues detailed below.  This is my first attempt at using c# with autocad so any pointers on what I am doing wrong will be well received.

1.  If add the AcDbMgd.dll and AcMgd.dll references and set copy local to false as the documentation advises then I get a FileNotFoundException, could not load file or assembly 'acdbmgd'.  If I set the copy local to true then the error goes away.

2.  I tried using the code below to add a paramater but I get an exception on the first line System.TypeLoadException: Method 'CopyTo'.

Autodesk.AutoCAD.DatabaseServices.Databasedatabase = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument.Database;

//Users builder to edit the summary info (file properties) of the drawing

Autodesk.AutoCAD.DatabaseServices.DatabaseSummaryInfoBuilder infoBuilder = new Autodesk.AutoCAD.DatabaseServices.DatabaseSummaryInfoBuilder(database.SummaryInfo);
string key = "test";
string value = "testvalue";
infoBuilder.CustomPropertyTable.Add(key, value);
database.SummaryInfo = infoBuilder.ToDatabaseSummaryInfo();