Well if it were me I would just reinstall CUPS to be safe:
slapt-get --reinstall cups
Then reset the printer using your browser and localhost:631, use LPT1 as the device, and try a different LaserJet driver (hpijs).
No dice. I reinstalled CUPS using slapt-get (the command line didn't work for me for some reason), and on trying to print a test page, I got "Quota limit reached", even though, according to the control center, no quota has been set. I also saw no way to select LPT1 as the device or select the hpijs driver from localhost 631.