I installed Debian 7.0 on another computer, didn't add users to lpadmin and tried to reproduce. I discovered some interesting things.
The problem with non-working CUPS web interface buttons were cookies. If cookies are blocked, the buttons don't work. There are simple ways to check this and display a warning if a browser cannot accept cookies (I can post sample code), I think this should be implemented. After I discovered this, I unblocked the cookies, logged in via my user/pass (sudo account) and I now receive error message: Add Printer Error Unable to add printer: Forbidden And log message: Returning HTTP Forbidden for CUPS-Get-Devices (no URI) from localhost That is much better, but still doesn't help me manage printers. So I tried with KDE systemsettings again. Adding/modifying printers via systemsettings works, if I run them with kdesudo systemsettings. It's clear that system-config-printer-kde should ask for administrative password, but it doesn't. I hope this information helps solving the problem. Best Regards, Andrej
