So, all of us who have amd64 machines have suffered heavily in the past few years. That goes for all 64 bit systems, but we were the first. :) The big problem is that everybody and their dog only release drivers for 32 bit systems, at least the cheap junk we always buy.
So when I did a 'full upgrade' to my big machine, I found I couldn't print to my laser printer. It only had an old 32 bit driver and no chance for a 64 bit one. That was a total nightmare and I solved it by a total new install. Thus, my older machine waited forever for an upgrade, and I finally had to do it.
So, when you do a full upgrade, the printer driver (filter program) won't work. This is Debian Multiarch. You used to be able to just load the 32 bit libraries, but you can't do that any more.
In root, type dpkg -i --add-architecture i386
NOT ENOUGH! as I found out.
Immediately do an aptitude update. Then when you reinstall your driver, it will tell you what 386 libraries are missing, and you can actually load them. Install the driver again, and it works.