I suspect you haven't seen the installation requirements. See PDF Output in the 2020 section of the RoboHelp Tour on my site.
I am having the same problem. I installed Java 1.8.0_261, as stated in Peter's RoboHelp Tour, but I am still getting the message "Java not found" in the output log. Is there anything else I have to configure? Do I have to enter the path somewhere?
Thanks for any help!
The only other reason it fails with that reason that I know of is installing the wrong version, 32 bit instead of 64 bit or suchlike.
Thanks Peter, that apparently was the case.