All install or remove attempts fail with dpkg: error: duplicate file trigger interest

I can't install or remove any packages right now. Every aptitude or dpkg command fails with

dpkg: error: duplicate file trigger interest for filename `/usr/share/icons/hicolor' and package `hicolor-icon-theme'

I tried the sed trick from http://askubuntu.com/questions/13484.../203056#203056, but that didn't work for me.

I'm running 12.10 with 3.2.0-32.