1. check your /etc/hosts file. make sure there is a line which reads something like:
127.0.0.1 localhost mycomputer (or whatever you named your computer when you installed Linux). Without that line, the system may not recognize "localhost", but it may recognize "mycomputer". I've tripped myself up with that oversight a few times.
2. Which distro are you using? most distros have service management utilities. find out which utilities your distro uses for printer management, and use that to try to add a printer.
3. If you are using the CUPS prining system, use a browser and enter the url
http://localhost:631 to get into the CUPS management utilities. use that to add a printer.
As a side note: with CUPS, you can have one physical printer, but you can set up several virtual printers depending on the printing tasks you most commonly need. each virtual is configured and named for the particular task. then, when you need to print something, select the appropriate virtual printer.