diff -Naur gnome-screensaver.orig/gnome-screensaver.pam gnome-screensaver/gnome-screensaver.pam
--- gnome-screensaver.orig/gnome-screensaver.pam	2012-03-14 12:21:55.469628377 +0100
+++ gnome-screensaver/gnome-screensaver.pam	2012-03-14 12:22:29.154260124 +0100
@@ -1,3 +1,3 @@
 #%PAM-1.0
-auth        required     pam_unix_auth.so
+auth        required     pam_unix_auth.so nullok
 auth        optional     pam_gnome_keyring.so