upon apt-get dist-upgrading, I couldn't print to my hp4050 anymore. Cups was looking for /usr/lib/cups/filters/cupsomatic which doesn't belong to the upgraded version.
Quick fix : cd /usr/lib/cups/filters ln -s foomatic-rip cupsomatic and it works like a charm my versions : ii cupsomatic-ppd 0.20010420-4 ii cupsys 1.1.19candidat ii cupsys-bsd 1.1.19candidat ii cupsys-client 1.1.19candidat ii cupsys-driver- 4.2.5-2 ii libcupsimage2 1.1.19candidat ii libcupsys2 1.1.19candidat John