xscreensaver: password initialization failed

Hello, I cannot unlock the screen with the latest version of xscreensaver. (xscreensaver-6.02-lp153.88.2.x86_64) I get the message "password initialization failed" in the unlock-window and when using the "--verbose" flag, I get this message on the terminal: pwnam: couldn't get password of "peter" There is no such problem with version 5.44-5.3.1. How could I get the unlocking working please? TIA for any hints, -- Peter