Isn't pretty but I think it's working.
I choose the "If Mohammed won't come the Mountain, the Mountain must come to him"-approach. I copied all the WP packages into Delphi7\bin after installing the components. Thereafter startup was problemless. The "Install package" dialog states (when clicking on a package) that it is looking into the Projects\Bpl directory - I don't think so anymore.
If anyone knows the right procedure I'll be very interested to know.
Delphi and 3'party components is Hell. It shouldn't be necessary to spend one working day reinstalling 6 packages!