First, I'm so terribly sorry that you have run into this. The expected file is indeed missing from the X-Pack distribution. This is a build issue on our side, and one that we take very seriously. We will work to address the breakdown that led to this.
You can fix this: create the missing file called
x-pack-env.bat with the following content:
Thank you so very much for downloading a pre-release of Elasticsearch, trying out X-Pack, and giving feedback here. We have a Pioneer Program for users like you. I will be adding you to the program. Again, thank you!