Reported on the forum: https://forum.gnupg.org/t/gpgol-web-installer-freezes-v5-10/7434/14 , specifically for gpg4win 5.1.0.

Current suspicion is that execution of the powershell script gets blocked (without returning an error code). Version 5.0.2 works for the reporter, so probably our runas fallback mechanism will do the trick - if we can figure out when to use it.