I was seeing this problem about once every two hours on my computer, so I restarted my session and immediately attached gdb to the gnome-settings-daemon process (and continued it).
It has not crashed since. The computer's been up for about 16 hours (not counting time in suspend) now. zw -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org