That example extension unfortunately will not run out of the box. The stored procedure in question is basically used to get configurations for different product types. So you can implement a config via the self.wedge_address_configs property.
Feel free to submit a Support ticket on the developer portal and we can help you get up and running.
It appears that the dbplan did not get run. It is possible that it is either not picking up everything quite correctly, or you just need to run q2 run_db_plan.