Einstiegspunkt nicht gefunden python.exe
Yes, I know this post is a bit old, but maybe someone else searches this.
I got the same error. And really, I just tried to start the python script via MS Powershell instead of CMD. I just wanted to use the PS one time.
And it worked, at least for me.
So, if you encounter this error, try to use the Powershell :)
Adventurous Albatross