Hi! I've just got the same message. In my opinion, the problem appears because "RevitNodes" is a Dynamo library (you can find the respective dll file in the Dynamo installation folder). As a result, when the Python script is run in Revit, it crashes since Dynamo is not loaded. I have removed this line and the script is working. Hopefully we don't need this library in the next steps.

Best

Periklis