No integration with Multiterm 2015 after installing and deinstalling Multiterm 2017

Dear experts,
after the installation of MultiTerm 2017 I'm having problems with termbase integration in SDL Studio 2017 and Passolo 2018. What I've already done and it did not help: deinstall MultiTerm 2017, repair MultiTerm 2015, deinstall and install MultiTerm 2015, repair Studio 2017, system recovery.
The current problems are:
- I can't integrate any termbase in Passolo. When I click on "Browse" to define the termbase location, I get the following error message:

- In Studio, the term recognition does work, but when I click on "Show term in the termbase", I get the following error message:

TIA, any help appreciated!
I guess I need to change some settings in the registry, but I don't know where to look for them and what to change.

Best regards,