Can't retreat either

[Harry Putnam <reader@newsguy.com>]

In an attempt to get away from irritating behavior in current cvs
gnus, (posted here under thread "Something very wrong", I backed off
to gnus_03 but find now I cannot open any groups.

Afer closing gnus and emacs, I reaimed gnus at the appropriate
directory of lisp files.  From gnus_04 to old gnus_03 installation.

Then removed all .marks and .overview files under ~/Mail.
Started gnus, who came up as the new (old) version, then ran 
M-x nnml-generate-nov-databases.

Only after that completed did I try to open a group.  Gnus won't let
me and throws an error that may be a clue about my earlier troubles
too.

Backtrace below, can someone see what the trouble is?
`gnus-correct-length' appears only in ~/.newsrc.eld.  Is not found in
any of the *.el files under my gnus_03 tree.  

In fact it appears in /usr/local/gnus_04/lisp/gnus-spec.el, from my
gnus current cvs directory.  So this is code added since gnus_03 and
might possibly be the source of my troubles.

How can I back up gracefully to a gnus that didn't use this code.  Can
I simply remove the section from .newsrc.eld that contains
gnus-correct-length?

========================================
Debugger entered--Lisp error: (void-function gnus-correct-length)
  (gnus-correct-length val)
  (> (gnus-correct-length val) 20)
  (if (> (gnus-correct-length val) 20) (gnus-correct-substring val 0 20) val)
  (let ((val ...)) (if (> ... 20) (gnus-correct-substring val 0 20) val))
  (format "%c%4s: %-20s%c" gnus-tmp-opening-bracket gnus-tmp-lines (let (...) (if ... ... val)) gnus-tmp-closing-bracket)
  (insert (format "%c%4s: %-20s%c" gnus-tmp-opening-bracket gnus-tmp-lines (let ... ...) gnus-tmp-closing-bracket))
  (progn (insert (format "%c%4s: %-20s%c" gnus-tmp-opening-bracket gnus-tmp-lines ... gnus-tmp-closing-bracket)) (point))
  (gnus-put-text-property (point) (progn (insert ...) (point)) gnus-mouse-face-prop gnus-mouse-face)
  (progn (insert (format "%2d%c%c%7s%c%s" ... gnus-tmp-unread gnus-tmp-replied ... gnus-tmp-score-char gnus-tmp-indentation)) (gnus-put-text-property (point) (progn ... ...) gnus-mouse-face-prop gnus-mouse-face) (insert " " gnus-tmp-subject-or-nil "\n"))
  eval((progn (insert (format "%2d%c%c%7s%c%s" ... gnus-tmp-unread gnus-tmp-replied ... gnus-tmp-score-char gnus-tmp-indentation)) (gnus-put-text-property (point) (progn ... ...) gnus-mouse-face-prop gnus-mouse-face) (insert " " gnus-tmp-subject-or-nil "\n")))
  gnus-summary-insert-line([0 "" "" "05 Apr 2001 23:33:09 +0400" "" "" 0 0 "" nil] 0 nil 128 t nil "" nil 1)
  gnus-update-summary-mark-positions()
  gnus-summary-mode("nnml:fw")
  gnus-summary-setup-buffer("nnml:fw")
  gnus-summary-read-group-1("nnml:fw" nil t nil nil nil)
  gnus-summary-read-group("nnml:fw" nil t nil nil nil nil)
  gnus-group-read-group(nil t)
  gnus-group-select-group(nil)
  call-interactively(gnus-group-select-group)