https://bugs.winehq.org/show_bug.cgi?id=40156
--- Comment #3 from rjwilmsi@gmail.com --- Retesting as after a couple of years there are newer wine versions:
wine 2.0.1 with winetricks dotnet20 => fail, same error as before wine 2.0.1 with winetricks dotnet40 => fail, same error as before wine 3.5 with winetricks dotnet40 => success, database scan completes without error (Jan 2018 enwiki, ~60 GB XML).
So from my testing issue has been resolved at some point between wine 2.0.1 and 3.5, so thanks to wine team.