Please describe the problem:
remote logging in a gnome session via gdm xdmcp chooser with a different 
keyboard type where a multimedia key is set to a keyboard specific key 
(e.g. "Help" button or "SunAudioMute"). 
This results in a XKeyGrab to "AnyKey". 

This means the keyboard can not be used. As this happen in gnome-settings-daemon
this effectively blocks the session.

Steps to reproduce:
Here is a simple way to reproduce without remotely login :

1. assign gconf key in /apps/gnome_settings_daemon/keybindings/volume_mute
 to "Help". (at this point your keyboard should be already grabbed)

2. logout and log back into a Gnome session



Actual results:
the keyboard doesn't work anymore as an AnyKey grab is performed in
gnome-control-center/gnome-settings-daemon/gnome-settings-multimedia-keys.c

Expected results:
a warning should be produced and the keybinding should be ignored if the keycode 
returned from the egg_accelerator_parse_virtual in init_kbd in
gnome-control-center/gnome-settings-daemon/gnome-settings-multimedia-keys.c 
is equal to zero (which means AnyKey for the subsequent keygrab).

Does this happen every time?
yes.

Other information:
Here is a small patch which fixes the problem :

Index: gnome-settings-daemon/gnome-settings-multimedia-keys.c
===================================================================
RCS file:
/cvs/gnome/gnome-control-center/gnome-settings-daemon/gnome-settings-multimedia-keys.c,v
retrieving revision 1.12
diff -r1.12 gnome-settings-multimedia-keys.c
451a452,460
>       /*avoid grabbing all the keyboard when KeyCode cannot be retrieved */
>               if (key->keycode == AnyKey)
>                 {
>                   g_warning ("The shortcut key \"%s\" cannot be found on the
current system, ignoring the binding", tmp);
>                   g_free (tmp);
>                   g_free (key);
>                   continue;
>                 }
>