Download the "Blender Text Counter" Add-on to make it work.
https://github.com/leomoon-studios/blender-text-counter
The text counter script seems to be broken again. It doesn't even install with 2.79a.
This was intended to make it easier for users to see what frame I was working on - but it has ended up being such a headache haha
I am not the maintainer of that add-on.
So just use the in-built frame overlay (metadata: frame)
If you unzip it and install just the single .py file it seems to be working.