Well, presumably this is an uncaught bug. paperconf -a should list all of it's known papersizes. paperconf -d should list the currently selected one. I imagine either the /usr/sbin/paperconfig script must have a typo in it. Both paperconfig and paperconf (first is for setting, second is for reading) seem to work fine in woody. paperconfig is a shell script, so it's easy enough to send if you like. paperconf may be your real problem, since paperconfig calls it to get all of the known paper types. It's a binary however. If more than one person is having this problem on upgrade, then a bug should be posted against it so the maintainer can fix it for the next potato update.
You might try $ dpkg --force-remove-essential --purge libpaperg followed by $ dpkg -i libpaperg*.deb DANGER: Careful with that --force stuff. -- Copyright © 2000 Megalomania Industries, Inc.