Just to indicate some replication, I also experienced this in the last few
days. Presumably it's just a incorrect version for the pam dependencies of
the kdm package, or something like that.
I installed kdm 4.2.2-2 from Debian Unstable on my amd64 system, along with
many other KDE4 packages. It left me with libpam0g 0.99.7.1-5. The KDM
login screen would load fine, but whenever entered a username/password and
tried to log in, I'd immediately get a pop-up error dialog indicating than
an error had occurred and that I should check the KDM log file(s) for more
information. (Unfortunately I don't have the exact error message text, but
it wasn't very helpful.) The /var/log/kdm.log file didn't have any useful
information, but I eventually discovered some suspect lines in
/var/log/syslog that pointed to pam. Notably lines like:
Apr 19 17:37:54 mira kdm_greet[9623]: Unknown V_xxx code 4 from core
Apr 19 17:37:55 mira kdm: :0[9607]: PAM pam_setcred: NULL pam handle passed
Apr 19 17:37:55 mira kdm: :0[9607]: pam_setcred() for izogi failed: System
error
Apr 19 17:37:55 mira kdm: :0[9607]: Client start failed
Apr 19 17:37:55 mira kdm: :0[9607]: PAM pam_setcred: NULL pam handle passed
Apr 19 17:37:55 mira kdm: :0[9607]: pam_setcred(DELETE_CRED) failed: System
error
[--snip--]
Apr 19 17:38:09 mira kdm: :0[11203]: PAM error: Bad item passed to
pam_*_item()
When I upgraded libpam0g from version 0.99.7.1-5 to 1.0.1-0 and
libpam-modules from 0.99.7.1-5 to 1.0.1-9 and the problems went away. (I
already had libpam-runtime 1.0.1-9 from an earlier occasion before
installing kdm 4.2.)
