Posting this for everyone who desperately needs this - it is the ultimate and apparently ONLY fix. (Apologies for the double post)
Don't try installing the software that came with your printer if you're using Snow Leopard. Get rid of the old and update via "software update".
I just found an answer on HP's website that specifically addresses the issue about what software to use with Snow Leopard. I haven't upgraded to anything newer since many of my other programs won't work with "non-Rosetta" status. Just to cap this thread off, hopefully with an answer to anyone desperately looking for help with this problem. The upshot is that you get rid of the old software and do a mac system update and voila - it works.
Here's the info from the HP site here:
https://h20566.www2.hp.com/portal/site/hpsc/template.PAGE/public/psi/mostViewedDisplay/?sp4ts.oid=3737540&spf_p.tpst=psiContentDisplay&spf_p.prp_psiContentDisplay=wsrp-navigationalState%3DdocId%253Demr_na-c01664444-45%257CdocLocale%253Den_US&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetokenMac OS X 10.6 Snow Leopard: Support details (Read Carefully)
Updated HP drivers compatible with Mac OS X 10.6 Snow Leopard are available through Apple Software Update .
Snow Leopard and Apple Software Updates : HP printer drivers, scan ICA software (using Apple Image Capture), fax drivers (where applicable) and utility are included in Snow Leopard. You do not need to reinstall or download any HP software for full print, scan, fax, and utility functionality.
HP software CD and Web downloads : HP provides full Snow Leopard software download from HP Software & Driver Downloads , and on the CD that ships with many printers. Please look carefully at the CD label to make sure that it supports Mac OS X 10.6.
NOTE: Software obtained directly from HP for All-in-One products includes the HP Scan. This software is installed in Macintosh HD\Applications\Hewlett Packard . For scanning, use the HP Scan application or Apple Image Capture.
Important : Older HP software is not compatible with Snow Leopard. Do not try to install earlier versions of HP software, either from the original product CD or from HP Software & Driver Downloads. The latest HP software that is compatible with Snow Leopard is included in Mac OS X 10.6. You will experience the best performance and functionality if you use the latest HP software.
There are several important HP software updates included in Mac OS X 10.6:
Printing
Full print functionality is supported with new HP print drivers included in Snow Leopard.
Scanning (where applicable)
The scanning interface is now built into Snow Leopard and supported through Apple Image Capture.
HP Scan Pro software (from Mac OS X 10.4, 10.5) is not supported in Snow Leopard. The HP icon for HP Device Manager still in the dock after upgrade is not functional and should be removed.
Scan support from pushing the Scan button on the HP product is not supported with this version of the ICA scan interface built into Snow Leopard. Scan functionality is supported by scanning directly from the computer.
HP Utility
HP Utility is included in Snow Leopard.
Faxing (where applicable)
HP fax drivers are included in Snow Leopard for supported devices.
Full print, scan, and fax drivers for HP Inkjet All-in-Ones (Deskjet, Officejet, and Photosmart) are included in Snow Leopard. Scanning is supported with the Apple Preview and Image Capture Applications in Snow Leopard.
Print drivers for the following printer types are included in Snow Leopard, and are available from Apple Software Update. These drivers provide print-only functionality.
HP Inkjet single-function printers (Deskjet, Officejet, and Photosmart)
HP LaserJet color single-function, All-in-One, and MFP printers
HP LaserJet monochrome single-function, All-in-One, and MFP printers
HP Designjet printers
Supported printers
The following HP printers are supported in OS X 10.8 Mountain Lion, OS X 10.7 Lion, and Mac OS X 10.6 Snow Leopard.
(All the Designjet Z3XXX printers are included)
HP Designjet Z2100 - 24 in Photo
HP Designjet Z2100 - 44 in Photo
HP Designjet Z3100 - 24 in Photo
HP Designjet Z3100 - 44 in Photo
HP Designjet Z3100ps - 24 in Photo
HP Designjet Z3100ps - 44 in Photo
HP Designjet Z3200 - 24 in Photo
HP Designjet Z3200 - 44 in Photo
HP Designjet Z3200ps - 24 in Photo
HP Designjet Z3200ps - 44 in Photo
HP Designjet Z5200 PostScript
HP Designjet Z6100ps - 42 in Photo
HP Designjet Z6100ps - 60 in Photo
HP Designjet Z6200ps - 42 in
HP Designjet Z6200ps - 60 in
