I am having a very odd problem with CUPS under sid. It works fine on two computers, but on another (with the same version of CUPS, installed at the same time, and with nothing particularly odd about the system config) I can only use the IPP backend.
When I try to add a printer from the web interface, I'm not even given the option of using anything besides the IPP backend (which is listed twice) or a disk file. As you can guess, this makes setting up a local printer more than a bit difficult. I've tried dpkg --purge on all the CUPS packages, deleting all of the config files just to be safe (well, really just the /etc/cups directory), and reinstalling all the packages multiple times, but the other backends just won't show up. They are there in /usr/lib/cups/backend, but for some reason CUPS is not detecting them. I can print to a network CUPS server with no problems. I'm really at a loss as to what the problem might be.