An ORA error comes from the oracle client libraries, so robot framework has successfully loaded the library and told it to connect to the database, but the oracle client is not configured properly so it didn’t connect.
This is where my help will be limited as I only once configured an oracle database connection to Loadrunner and that was ~10 years ago, so I’m no expert here, I do remember when I got to this stage it involved editing configuration files that the client uses.
One great thing is that ORA errors are well documented and you can search the error number, e.g when I searched for just "ORA-12541" I found this: