The tool is likely running correctly, but based off the results it sounds like some or all of your features do not belong to a subnetwork, you can learn more about the meaning of this attribute by reading the Is Connected Attribute topic in the online help. Have you created any subnetwork controllers for this area yet? If you follow the instructions in that page it will walk you through the process of how to create a new subnetwork (if you haven't already) and how you can update your subnetworks so those features will show as connected.