My problem seems to be solved, after:
1. I saved the "Mediaportal"-folder
2. Deinstalled Mediaportal (complete remove)
3. Installed the MePo x64_1.38.003
4. Installed MP-TVSeries4.5.1.745
5. Deleted the "Mediaportal"-folder in TeamMediaportal and inserted the one from step 1
Now I can import...
Thanks to all who solved the problem!
In my case, it's not yet all ok:
After "no mtch was found" I added <series>.tvdb for
House of the Dragon Season3
Interview with the Vampire Season3
The Paradise Season2
The Hardacres Season1
After restarting the import wizzard there was still "no results...