Adding Reference in Microsoft Visual Studio .NET 2003

[blastthisinfern]

I'm trying to write a program in C# and I need to use the Grid class from the MSDN library. MSDN says its in the PresentationFramework.dll file, and I have it on my computer. To save on typing here's whats happening http://img.photobucket.com/albums/v2...dioError-1.jpg .
The .dll file I need is in this folder:

C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0

and the other ones such as System.Windows.Forms are in:

C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322

I don't know why they're separate, or if that matters.