Presumably this is because the wrong HP drivers are installed. Visit http://www.hp.com/support/
If the driver is not available for your operating system, you may need to ensure both the Mac and the printer are on the same closed WiFi network, and use the Option key when you click the + sign below the printers to add the printer in Apple menu -> System Preferences -> Printer. Verify with the printer settings on the printer what the IP address is for the printer if it does not appear.
Short of that, you'll want to see if a PPD exists for your printer for the Mac. The Laserwriter 8 drivers support many postscript printers from HP.
Not knowing your Mac OS version in Apple menu -> About This Mac, or your model number or make, we can't help you further.