Buried in here somewhere is a method of using the Vista 64B driver. It was a a while ago but I was able to get mine working.
Here it is, a post by ibarron
"I'm using win 7 64bit. I couldn't get the z3100 drivers to install via the install script ... but ... unpacking them then using the windows 'add a printer' and pointing to the install files worked perfectly :-)
HP preview and APS doesn't work but the driver works.
HOPE THIS HELPS.