Aah, ok - I think
that the hint that I implemented giving instructions how to take Olaf's pistol is kind of unclear and mistakable...
Ok, let me try to reconstruct what your problem is (to make clear that there is no misunderstanding):
The hint appears and you (correctly) try to do as it says.
Open Olaf's gear and make him drop his pistol.
After this you try to take it by pressing Nehmen while still in Olaf's gear screen
Is that correct?
You can't take his pistol this way - I tested it with some random units.
You will have to leave the gear menu and walk to the spot where the pistol is and press "Gear" to enter your own
gear menu. There you should be able to take the pistol, resp. the Take button should work correctly.
What I will do is to improve the hint so that it explains better how to take Olaf's gun.
I really hope that I didn't misunderstand you - if yes, I'm sorry, mate!