If the gnubg.org site is not working, you can download gnubg ver1.02 from GreedyGammon AWS storage site.
That is the version I am using.
So it seems gnubg.org is having some issues with the new privacy rules in the EU and they decided to temporarily disable the main page. But some direct links to some inside pages still work. Here is the link to a list of Windows gnubg downloads.