I just observed this same problem after upgrading to Ubuntu 10.04.1 LTS, and Dakai Zhu's suggestion above again fixed it, EXCEPT that I also needed to re-start the CUPS daemon afterward: $ sudo service cups start
Restarting the CUPS daemon was suggested at https://bugs.launchpad.net/ubuntu/+source/system-config-printer/+bug/568831
I just observed this same problem after upgrading to Ubuntu 10.04.1 LTS, and Dakai Zhu's suggestion above again fixed it, EXCEPT that I also needed to re-start the CUPS daemon afterward:
$ sudo service cups start
Restarting the CUPS daemon was suggested at /bugs.launchpad .net/ubuntu/ +source/ system- config- printer/ +bug/568831
https:/