iPhoto calling to home network server that no longer exists
I had to replace a network drive I was using as a home server some time ago, and now whenever I go to the Desktop & Screensaver prefs pane, I get a message indicating "There was a problem connecting to the server newserver2".
This turned out to be coming from iPhoto. If I move my iPhoto Library to the desktop, then launch the Desktop & Screensavers prefs pane, I don't get the error message. When I put the iPhoto Library back in the Pictures folder, the error message returns.
At some point in the distant past, I imported some pictures from that server into iPhoto, and now for some reason the prefs pane in question wants to access that source. Launching iPhoto doesn't give any error message.
I've poked around in the database & plist files inside the iPhoto Library package, and looked in the Preferences for iPhoto, but have not found any reference to this old server. Any suggestions?
iMac, OS X Mavericks (10.9), Mid-2007 iMac 6GB RAM 1TB HD