If there’s already a GitHub issue about it, then the developer is already aware of it. Rather than open another issue, you should add your information to that existing issue – including the fact that the suggested fix didn’t work.
This seems like a very unusual error to get in Anki – since Anki would have to be running, with the add-on installed and enabled, in order for you to see this message at all.
If the developer continues to not respond, you should consider the add-on has been abandoned, and find a different solution for yourself.