KCMInin closed unexpectedly (nomachine)

I’m using FreeNX under Leap 42.1 x64 on a big server (128G / Opteron x48), and my users log in with their !Machine clients (running under Win7) into KDE. I had this running on OS 13.1, but after updating to 42.1, the !Machine client seems to connect OK, and I have a mouse and desktop background remotely, but after the splash screen, the KDE crash handler reports “KCMInit closed unexpectedly.” It says also that kdeinit5 segfaulted. This is all in KDE mode (but panes doesn’t appear). The Activities button is present in the screen corner and works as expected.

In the crash handler it says something about /lib64/libthread_db.so.1 - but that may be the crash handler…

This sounds vaguely familiar, but can’t seem to find a useful thread.

Thank You for any help,
Patti