pkexec pam_ck_connector(polkit-1:session): cannot determine display-device

This seems to be a fairly common syslog error message, it is found all over the internet:
pkexec pam_ck_connector(polkit-1:session): cannot determine display-device

The solution might be in this file:
/etc/pam.d/polkit-1

#%PAM-1.0
@include common-auth
@include common-account
@include common-password
session required pam_env.so readenv=1 user_readenv=0
session required pam_env.so readenv=1 envfile=/etc/default/locale user_readenv=0
@include common-session

where polkit needs to be made aware that we are most often on display 0:0
perhaps some of these go away with the newer version 0.106
http://hal.freedesktop.org/docs/PolicyKit/