Do either of you have the correct driver installed on your Mac? Macs are often really picky when you share some printers off a Windows box, or more correctly, the Windows box is picky about sharing with a Mac, if the Mac doesn't have the right driver for the printer.
Samsung printers are kind of on the fringe when it comes to compatibility-not with one particular operating system or another, but because they use their own PCL. My ML-1430 laser printer works fine on my network with Windows machines, but, but I haven't found a real network driver for OS X.3 yet, so it doesn't do everything for my iBook that it will for Windows.