I've just reflahed my N810 and found the same problem (Won't install the Tuning app due to missing Python file), I found a workaround that's easy and works, if it helps anyone. Before you try installing the Canola Tuning app, install MediaBox as that installs the relevant Python file itself, then install the Tuning app.

Not the perfect solution I know, but as I say, it worked for me.