Don't know what triggers this:

Trying to use C-x d (dired)

in emacs-version "21.0 \"Corsican\" XEmacs Lucid" leads this [2 *Backtrace* <application/octet-stream>] Signaling: (wrong-number-of-arguments #<compiled-function (from-key to-key) "...(51)" [(nil (shift) (control) (meta) (alt) (shift control) (shift alt) (shift meta) (control alt) (control meta) (alt meta) (shift control alt) (shift control meta) (shift alt meta) (control alt meta) (shift control alt meta)) nil prefix --dolist-temp--79744 define-key function-key-map append from-key vector to-key] 8> 1) dired-read-dir-and-switches("") call-interactively(dired) [3 <text/plain; US-ASCII (7bit)>]

After (load-file "/export/home/tmp/packages-21.0/lisp/dired/dired.el") dired works again.