HP 1310 Series AIO Printers -- HOW TO SCAN ---
1) Remove all programs from applications folder dealing with HP (I just moved entire folder to trash)
2) Download the latest software suite from HP
3) Once the dmg mounts, do NOT run the program. Instead, right click and show package contents.
4) Go into Contents--->Sub Installers---->Scan
5) Run those three installers (HP AiO Scan; HP Scan Pro; HP Scan Pro Help)
6) The files will install in /Applications/Hewlett Packard
That's it! I opened the HP Scan Pro program, and voila, scanning bliss!!! Necessity is not only the mother of all invention, in this case it's a kick in the rear to fix a problem for yourself rather than waiting on a company who seems to be slacking in it's customer support base.
Hope this helps! This may work for other models of HP AiO, but I can't guarantee that.
Al iMac 20 inch 2.4 GHz, Mac OS X (10.5.1)