Paint.NET :: Read PDN In C# Program

I try to read PDN file in my C# 4.0 program (coded with Visual Studio 2010 Express).

I have added references to :
- PaintDotNet.Base
- PaintDotNet.Core
- PaintDotNet.Data

For the beginning I try something simple :
string uri = @"..\forest.pdn";
string nom = "";
FileStream fs = new FileStream(uri, FileMode.Open, FileAccess.Read);
Document doc = document.FromStream(fs);
for (int i = 0; i < doc.Layers.Count; i++)
{
Layer current = (Layer)doc.Layers[i];
if (nom != "") nom += ", ";
nom += current.Name;
}
lblLayers.Content = nom;

But, when the program try to open a stream with "Document doc = document.FromStream(fs);" I have the following error :

Unable to load DLL 'Native.x86\PaintDotNet.Native.x86.dll': The referenced assembly is not installed on your system.

The Dll exists in my computer. I have tried to do what is indicated here, but without success.