Unable to open file! So what is " save file path"?

[CCA1550]

I used python way to run playbackExample.py, after the program asked me to select a option
and I choose 1. Record X-Plane, the first parameter is asked me "Enter save file path:", I try to write a desktop path or the path of X-Plane11 main, but finally I received Unable to open file!
What happend??