2008 was another age and time...

Sometimes I feel the internet is the closest thing to a time machine we have right now.

Note the year of the posts before yours. This is a very old topic and likely no longer relevant, as Firek appears to be talking about the old GOG Downloader.

Is your issue with FDM?
I use that most of the time now to download from GOG.

To use it correctly with your browser, you need an additional addon.
I set mine up for use with the ALT key, held down when I click a browser link in my GOG library.

There are better ways to use FDM now, with its very limited command-line, but that also requires curl.exe and a cookie file and being somewhat savvy.