Meanwhile, and with the help of Mentor support (thanks!) it turned out that the root cause is related to AATK. As soon as I remove AATK from my WDIR environment variable the issue has gone. Looks like I need to dig into the different AATK related rows in scripts.ini, which had just been copied from the previous 7.9.3 installation.
edit Aug. 10th, 2016:
What I had do do in detail is commenting out the row
script#6=%AATK%/FlipChip/Startup/ODBPP_Compatibility_Check.vbs
in scripts.ini
