Hi MeliBee,
this problem is now solved by the support team of Stardock (thank you Travis
). It was a missplaced serial in Window Blinds 6 and DeskScapes which I managed to remove now with "Impulse". Now everything is updating and working fine again.
But I have another question about the themes of "MyColors", here is the post for this problem:
https://forums.stardock.com/328108
If you have a suggestion for this please let me know.
Have a great weekend all of you here in the forums 
Greetings Saphire