gnome-screensaver-command from cron gives DBUS error

[Brian Mury]

I can use "gnome-screensaver-command --lock" to lock my screen (running
FC5).

I have a crontab entry to do this at specified times. It was working
until recently, when I started getting errors that say:

"gnome-screensaver-Message: Failed to connect to the D-BUS daemon:
Unable to determine the address of the message bus".

It still works from the command-line, just not from the crontab entry.

I have no idea what this error means or how to fix it. Suggestions?