So after a while we tried to open and close the Part Editor in the Layout tool.
This brought the situation where I could close the Layout tool.
When I reopend Layout, it said that integration was needed. So I obliged.
Now it shows me a different king of error: the partions seems to be locked by me.
I tried to delete the work directory in PCB and did the whole process: A new package, a new start of Layout and it keeps telleing me that the partion is reserved by me. :-)
Any good ideas?