Hi, The short answer is I do not know why you are getting this error.
But the code I posted will work with only one of the many ways of running Open Z-Wave. It will only work if you are using the new OpenZWave Add-on and OpenZWave (beta) Integration, that communicate via MQTT.
I have not followed it myself but I found this post describing the setup.
https://community.home-assistant.io/t/get-openzwave-beta-working/200121
If you do not recognise the steps involved then my code will be of no use to you.
Good Luck