Disabling F1Res helped. Thank you. But since this bug was reproducable and I was able to trigger it easily, I installed F1Res again and fiddled around with the F1Res properties. Change 1 thing -> load savegame -> crash -> change the 1st thing back and change another thing -> repeat. With this I narrowed it down to ONE thing: In F1Res screen preferences changing the 32 bit to 16 bit prevented the savegame to crash when I clicked on the world map. This evening I am going to play a little bit and see if the crash comes back again. Thank you for your help. This is (to say this again) the most ambitious mod for the original Fallout. EDIT: Nah, this was not it. I don't know, but now I get the crashes again on the world map.