AFAIK, there is no Terminal command to reset the printing system. This question was asked a while ago for Leopard and this was the answer then - don't know if this has changed for SL. The CUPS man pages would suggest it hasn't...
But there is now the ability to reset the cups daemon configuration file via the CUPS web page. Using your browser, open the CUPS Admin page
http://127.0.0.1:631/admin
Here you will see the button 'Edit Configuration File'. Click this and you will see the cupsd.conf entries. Looking through this file shows that network shared printers are browsed using "BrowseLocalProtocols CUPS dnssd", the same as you tried to enter with the other command which could be only for 10.5?
Anyway, here you will also see the button 'Use Default Configuration File'. Click this and then click Save Changes. This will prompt for your admin username and password. Enter these and OK. Hopefully this gets you back the ability to access Print & Fax and to print again.
Pahu
Message was edited by: PAHU