Users, which account information is obtained by ypbind from another
machine, locking the terminal with klock are not able to unlock the
terminal. Giving the correct password, klock says "failed".
Users with a local account don't have this problem.
Please check your PAM settings (/etc/pam.d/kde) and version.
Looks like a misconfiguration.
My PAM settings are (/etc/pam.d/kde)
auth required /lib/security/pam_pwdb.so shadow nullok
auth required /lib/security/pam_nologin.so
account required /lib/security/pam_pwdb.so
password required /lib/security/pam_cracklib.so
password required /lib/security/pam_pwdb.so shadow nullok use_authtok
session required /lib/security/pam_pwdb.so
session optional /lib/security/pam_console.so
My PAM version is pam-0.68-8
Should be fixed in the current version.