connection failed to via xdmcp

[Abdelkader Belahcene <abelahcene@gmail.com>]

Hi,
I ve tried to connect to server via XDMCP, (I am using debian lenny with
gnome). Following the doc I ve just to enable in gdm.conf , [XDMCP]
section, Enable=true. On some machines it ran, on other it didn't ???

When I ran on distant client xdmcp chooser, the server didn't appear,  I
enter manually the address, I tried to log, but it failed (the screen
became blank and frozen). I suppose it tried to connect in vain.

Finaly I discover, may be, this  is the error, in  /var/log/auth.log the
following

Apr  1 18:06:48 localhost gdm[3904]: PAM unable to
dlopen(/lib/security/pam_gnome_keyring.so):
/lib/security/pam_gnome_keyring.so: cannot open shared object file: No
such file or directory


It seems strange for me, I install in the same way the system ??   I
didn't install amnually anything about PAM, on any machine!!!

  how to correct it? 
how to install the missed lib, pam_gnome_keyring.so

thanks for help
bela