Hi Joris, All is well.
The error definitely means that the interop handle returned is null and BindSharedTexture would not work.
The thing that comes to mind right away is that 2.006 is using DirectX 9, but then the demo sender reports using DirectX 11. You can test any difference with with 2.006 SpoutSettings. 2.007 uses DirectX 11 only.
2.007 SpoutSettings has a more comprehensive diagnostic with log. If that says “Compatible for OpenGL texture sharing” there is something else going on. Paste he diagnostics here so we can see the result.
I will think a little more about it.
Edit: Forgot to ask - is this receiving or sending? Does the error occur for both?