Rob, you might want to take another crack at this. The integration had trouble recently as evidenced by lots of feedback in the other Harmony thread, but is working again for several users.
Remove all Logitech SmartApps from ST. Check your Harmony account to see if you have any unused, old and/or offline hubs. If there are any, either remove them or make sure they are connected as ST will try to discover all Home Hubs in your Logitech account and fail if one is offline. Then follow the instructions in the below post to start the integration/hub discovery.