I'm completely new to Python for .Net, and I actually have very little experience with Python and no experience with C#. So please forgive me if my question seems very basic. I'm using Python 2.7.3, and I downloaded pythonnet-2.0-alpha2-clr2.0_131_py27_UCS2 and unzipped it into a folder named pyfornet_test, which also contains the dll I'm trying to use (called DotNet4Class.dll) Then I run this: import sys import os import clr sys.path.append(r"C:\pyfornet_test") clr.AddReference("DotNet4Class.dll") Which gives me this error: System.IO.FileNotFoundException: Unable to find assembly 'DotNet4Class.dll'. at Python.Runtime.CLRModule.AddReference(String name) in C:\Users\Barton\Documents\Visual Studio 2008\Projects\PyShar p\trunk\pythonnet\src\runtime\moduleobject.cs:line 375 Any advice would be much appreciated. Thank you!