Comment 15 for bug 6711

I also had a similar bug. Symptoms were:
- the usb printer was correctly listed by lsusb
- gnome-cups-manager didn't auto-detect the printer.
- manual install of a printer had no effect

Solution: delete the line starting with Servername in /etc/cups/client.conf

Background info: I build a local network, somewhere in the network was a cups-server installed. When this server was running, a manual added printer resulted in a message like: "password for user root on 192.168.1.34:". When the server was shut down, the message was: "IPP request failed with status 1280". (remember: When gnome-cups-manager is started from the command line, debug information will show on the command line.) It looks like the gnome-cups-manager disregarded the cupsys server running on localhost.
The distrubution in use is: Ubuntu Feisty Fawn, gnome-cups-manager --version output gives: "GNOME gnome-printer-view 0.31"