Unable to load reference in XAML

[Eraknelo]

Hello,

I've been trying out some of that 3D stuff lately. And downloaded the 3DTools.dll from codeplex wich was needed for this tutorial.

Now, they don't actually say that you have to import anything, but that's clearly needed. I added the 3DTools.dll to the references, and added:

xmlns:x="clr-namespace:_3DTools;assembly=3DTools"

to the window, to load it into the XAML. But that line of code returned this error:

Unable to load the metadata for assembly '3DTools'. The following error was encountered during load: Could not load file or assembly 'file:///C:\Users\Rene\documents\visual studio 2010\Code Snippets\Visual Basic\My Code Snippets\3DTools.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)

I have tried EVERYTHING, but I can't find the sulution! Please help me!

Thanks, René.