I got also the same problem. The solution for me, was to set up the lo device (local loopback). That should be done at boot time, but for some reason it does not work at my Ubuntu. Check your Network devices at Terminal Promt by typing "sudo ifconfig -a". If you would not get loopback address 127.0.0.1, your loopback device is down. Set it up by typing "sudo ifconfig lo 127.0.0.1". For me that was also the reason for many other problems. "Netstat -noap" -command reveals you that CUPS server uses 127.0.0.1 loopback.
I got also the same problem. The solution for me, was to set up the lo device (local loopback). That should be done at boot time, but for some reason it does not work at my Ubuntu. Check your Network devices at Terminal Promt by typing "sudo ifconfig -a". If you would not get loopback address 127.0.0.1, your loopback device is down. Set it up by typing "sudo ifconfig lo 127.0.0.1". For me that was also the reason for many other problems. "Netstat -noap" -command reveals you that CUPS server uses 127.0.0.1 loopback.