Getting "Failed to find command GUBP" when running AutomationTool

Check this answer out. I was having the same issues and it just looks like the phrasing of how this is done has changed quite a bit since the post you linked was written.

Here’s the documentation detailing the new syntax:
https://docs.unrealengine.com/latest/INT/Programming/Development/BuildGraph/index.html
https://docs.unrealengine.com/latest/INT/Programming/Development/InstalledBuildReference/index.html