Hi Nicolas,
you can try to download and install metanumerics http://metanumerics.codeplex.com/downloads/get/716529.
It seems that in this way the bug is fixed.
If the bug persists, copy meta.numerics.dll from C:\Program Files (x86)\Meta.Numerics to C:\RhinoOpenSourceCode\Lib\Meta.Numerics.dll
Finally try to restart windows.
Let me know. Best,
g
The error message is incorrect, because the file exists but is not loaded.
In fact, because you distribute by ZIP file, the DLL gets blocked by Windows during unzipping.
Right-click on the Lib\Meta.Numerics.dll file and select “Properties”, then click “Unblock”. The Python script will now load the DLL.