Facing the same problem. The good old LaserJet 1020 worked well for a long time, then apparently some problem with the driver installation occurred. No clue what exactly happened. Even removing the driver does not help - my Win XP environment keeps asking to install firstly for the file sdhp1020.sdd (which I could somehow find), and then continues asking for zshp1020s.dll.
I already completely removed the HP printer divers from my PC (So far I did not remove my scanner environment, which is still working fine).
Any help is highly appreciated!
Thanks for your attention, b/rgds