Some good soul has a working download link for:
HP Designjet Z3100 Series Raster Driver Installer from 61.73.361.41 /23 May 2008
Tried with Firefox and IE, in german and english - nope, niente, nichts - no working download link.
PS: Seems that the HP ftp server was at lunch, the download is working now.
ftp://ftp.hp.com/pub/softlib/software10/C...PhotoSeries.EXE