Undefined subroutine in tl-installer-windows

[Davide Campagnari]

First time I've ever had troubles... I'm trying to install TL2021 on a
Windows10 machine with
   install-tl-windows.exe
as administrator; the installation wizard starts, everything looks
fine but as soon as the installation starts it fails with a warning
about an undefined subroutine
   @TeXLive::TLWinGoo::is_vista

Best regards
Davide Campagnari