price quote update cron job failing

[Stuart McGraw]

As described in the Gnucash documentations, I have
recently set up a personal (runs under my userid, 
not root) crontab entry to automatically update my 
stock prices:

  0 2 * * 6 gnucash --add-price-quotes postgres://stuart@localhost/gnucash

However, when it ran last night, I got this email 
back:

  GConf Error: Failed to contact configuration server; the most
  common cause is a missing or misconfigured D-Bus session bus
  daemon. See http://projects.gnome.org/gconf/ for information.
  (Details -  1: Not running within active session)
  Found Finance::Quote version 1.17

I gather this has something to do with not running 
in a gnome session (and in fact the same command 
works fine when run in a xterm window).  

Unfortunately I have no idea how to fix.  Any
suggestions?  Am running this on a Fedora-15 
system.  Thanks....