That's probably the rig index that you are using. Rig index start from 1 and if select, say, -r 4, but you only have 3 rigs in your list it will fail with that error.
I need to improve that error handling.
Oh sweet. This error occurs just by launching the program, but manually setting the rig index (in my case -r -4) the program appears to run. Will have to setup again as I purged grafana and influx already.