hsqldb.jar not found with LO 7.2.1.2 and Split database

[Johann-Tree]

When opening a split database with LibreOffice 7.2.1.2, created with the wizard viewtopic.php?f=83&t=61183 , I now get the following error message:
hsqldb.jar not found
When canceling the dialog, everything works as expected and as it did all the years before.
This is confusing.
What is the reason and how can it be solved?

Thanks!