Comment 15 for bug 990388

Fix as described in askubuntu #7 worked for me. I copy it here for reference with some adaptions, credits go to RobDavenport.

== Set up printer shared on a sambe network with authentication ==

    Choose Add new printer in Printing, click open 'Network Printers', select 'Windows Printer via SAMBA'

    Click 'Browse' to browse for printer (it prompts for authentication to access Windows server with printer)

    or enter 'smb://sambadomain/servername/printername' e.g. smb://uclv/printers.mycompany.at/a4-e105

    Select 'Set authentication details now'

    Enter details as 'domain\username' and password
    (if you click 'verify' now it will say printer is not accessible, but click Forward anyway.)

    Select driver

    Print test page

Just to be clear: I always could print from Ubuntu 11.10, but not from 12.04 Desktop to printers served by a Windows server.
If I rename a printer, I get again the authentication error. The above set up worked.