Looking at your errors, I believe that you have not set your environment variables correctly. Please make sure to set the environment variables described in Step 1 of the readme here: https://github.com/HebiRobotics/hebi_gazebo, and that should ensure that your model loads up correctly. To be sure that you're up and running, be sure to check Scope to see if:
- the modules pop up in the bar on the left
- you are able to send commands / receive feedback in the monitoring tab of Scope