megallag65: I had a tough time of installing the update to 2.0.3., my version was 2.0.1. Every few minutes the download would fail and indicate a network error.
I managed to get mine installed with the below solution. This worked for me, but might not be viable for some.
1. Uninstalled Pathfinder: Kingmaker completely.
2. Allowed the GOG Galaxy Client through the Windows firewall, in my case, Windows 10.
3. Connected to a server with my VPN to a fast internet infrastructure country. This seems to have added some stability, at the cost of some speed.
4. Started the install from the Galaxy Client.
After all that, my install went without a hitch.
Perhaps this method will work for you.
Maybe some of this was not necessary, but it worked for me, after days of failure!
Good Luck folks!
Still viable option to fix same problem. Thx. I'm really surprised what GOG still did not fixed this.