Ok,
first thanks a lot for your help!

I did as you told me. The problem now is that the wrong thing is captured.
HTTrack now captures www.kaufmich.com, but not the forum with its threads and
posts?
And then, if I would figure out a working solution:
How do I exclude the logout button? What command do I need to enter, the link
of the logout button is:

www.kaufmich.com/forum/entry/signout/E714NDNNVCPA?Target=categories/discussions