I have installed a Samsung ML 1510 printer on a Windows 2000 PC and had some problems printing to it from a Linux SuSE 9.1 machine.

The network was accessible, file shares could be seen, but for the printer it was"access denied".

There are a couple of things that I had to do to get this working.

The first step is as root to execute the command:
lppasswd -g sys -a root
The root is password is requested.

Next using kprinter, I had to scan as anonymous in order to see the machines on the network, then go back to the previous kprinter page to add the name and password of the Windows user with admin rights. I went on again to the page showing the network, and added the printer.

See here for an explanation from SuSE re. 9.1

Then I could print. :-)

Printer configuration is kept in /etc/cups/printers.conf