Hello Julian,
From your description, it sounds like your Web browser tried to display the contents of the licensing packages file, rather than downloading it.
Please try:
- Go to this page: https://www.hauptwerk.com/licensingpackages/
- Right-click on the black 'License package' button, and select 'Save ... as ..' (or whatever terminology the particular browser you're using has for it). You need to make sure that it actually downloads (saves) the file, rather than just displaying it. (In case it's easier, the direct link to the file that you need to download is: http://downloadhauptwerk.com/hauptwerk/ ... ptwerk_rar ).
- Once the file has downloaded, in Hauptwerk v5, use 'File | Install ...' to install that downloaded file (i.e. HauptwerkLicensingPackages.CompPkg_Hauptwerk_rar ).
Does that solve it?