Wrong type argument:listp, \.\.\.

[Frank Fredstone]

I'm using emacs 22.0.50.1. Usually, (after running and quitting gnus,
maybe) I get an error when trying to exit emacs:

Wrong type argument:listp, \.\.\.

Debugging on error gets me:

Debugger entered--Lisp error: (wrong-type-argument listp \.\.\.)
  save-place-forget-unreadable-files()
  save-place-alist-to-file()
  save-place-kill-emacs-hook()
  run-hooks(kill-emacs-hook)
  kill-emacs()
  save-buffers-kill-emacs(nil)
  call-interactively(save-buffers-kill-emacs)

I don't know off hand what to look for. Do you know a solution?