Utility Network Activities

Hi

I am trying to use the Utility Network activities from the ArcGIS Utility Network REST API Activity Pack v. 5.1.0. I have a simple workflow with only the “Initialize Utility Network” activity.

I have added this workflow to a VertiGIS Studio Web application. The application uses a single webmap with all the UN layers from my UN service. When running the workflow I get this error message.

Anybody having seen this error? What am I missing? In the help section of the activity it says “Initializes the utility networks from the given web map”. I can't find a guide on how by build my webmap.

- Jesper