The way i did it.
Open your GTL folder.
Click on LOCAL_IP_BACKUP_LOBBY.
In my case, i already had 81.3.59.61 written in there but without the
www.gtl-server.net.
I just added the addy next to it so it would be 81.3.59.61
www.gtl-server.net as instructed. Went on GTL and voila...online files working again.
That was the only thing written in there so if 127.0.0.1 localhost
www.gtl-server.net is in there then i'm guessing that you replace it with 81.3.59.61
www.gtl-server.net and your back in business.