> PS launches and opens fine using the Pagestream Assign icon, but it doesn't open
> when clicking on the Pagestream default app icon. Of course, as this was a direct
> copy of my old installation my user-startup doesn't contain the PS script. Can I
> add the script manually to the user-startup? If so, what should be the script?

I guess the answer might be contained in one of those threads of yours:

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=9585&forum=16
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=9592&forum=9