According to the developer's official website, The Golfer's Diary has been discontinued and registrations are no longer available. Since the download from the application's Software Informer page still works, you can download and install it on your PC, but you will only be able to use it for 9 days as there's no way to register the program to make it function further.
In case you need an alternative solution, I recommend checking out ScoreKeeper.
