You get this warning because gnome services such as
gnome-settings-daemon are not normally running when you are logged into a Xubuntu or Xfce session.
However, the quick fix that has worked for me is to go to the menu and choose settings > settings manager > session and startup > advanced and enable Gnome services (see screenshot below). Now, all installed Gnome services will start when you login, and you should be able to use the functionality of
gnome-keyring-daemon (although further configuration may be necessary, as I note below).
It is important to note that you will have to logout and login again for this to take effect, and then services such as these will be running (if you have already have installed them with gnome applications):
You may need to tweak other things in the Xfce/Xubuntu session, depending on how you wish to use
gnome-keyring-daemon. There are some references to using it with ssh on this blog and many others out there, but there can be problems to overcome with using it on Xubuntu.
It is too big of a topic to produce a general answer on the pros and cons of
gnome-keyring, but these hints should enable you to begin integrating it into a Xubuntu session.
However, if these suggestions don't solve the problem, you may be a victim of the problem described at Launchpad regarding