Alright, something strange but positiv for me:
I copied the tabels into the mediaVP and still got the old original german missions in the global data folder... and it works! 14 warnigs on start up but it works! And it is german. And I can copy in old translated revenge missions, too (they suppose to be a bit less buggy, but I don't know...) and it works, too.
Of course it was too fine to be true: Some triggers don't pull so the game does not really detect that I actually won a mission sometimes. But that's ok since I can finish up the mission via cheats. It's not that bad, because you still can collect every information you need (and I noticed only a few of such corrupted missions).
But now I'm stuck in mission 30 where earth's beam canons should fire on my marked targets but it does not. Of course I could skip this mission using the cheats, but here I don't want to do that. I did play up to mission 60 (somewhere around there) the last time I play it so I do remember some facts but I don't want to miss a whole mission like this now.
I can imagine that the original author's idea of placing a beam gun origin near the planet image in the background doesn't work with SCP anymore, but maybe it is possible to place something new tiny that far away and let that thing fire the "earth protection beam" ?
Or any other ideas?