It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

How add correctly new tracks and cars to gog version? I have version with patch 1.2 and shows me error, when I want launch news tracks.
My a problem is solved.
For future reference, using RVGL might be wiser since it has a launcher which itself can manage downloads for you.