Lisp Mode Hook when entering ZWEI for first time

[Mark J. Dulcey <Dulcey at MIT-AI>]

In ZWEI in Remote-File 7.0, LMFILE-Remote 15.1, MIT-Specific 7.0,
System 85.23, ZMail 44.3, microcode 117, 60.45Hz, on Lisp Machine One:

In my init file, I had the following line:

  (setq zwei:lisp-mode-hook #'zwei:com-return-indents-mode)

When I first entered the editor, I got the following error message:

>>>>TRAP 15453 (TRANS-TRAP)
The instance variable ZWEI:*NUMERIC-ARG-P* is unbound in #<ZMACS-TOP-LEVEL-EDITOR 23601355>
While in the function ZWEI:COM-RETURN-INDENTS-MODE  ZWEI:TURN-ON-MODE 
ZWEI:TURN-ON-USER-MODES

ZWEI:COM-RETURN-INDENTS-MODE:

If I got out of this error trap by typing Resume and supplying the value
NIL, the editor works, but I now have TWO BUFFER-1 buffers!
Furthermore, selecting the older of these gets me into a strange losing
mode where the editor won't accept any commands (not even printing
characters!).  The only way to recover and return to a working editor is
to use System/Control-E to get a brand-new buffer, and then one can use
Control-X Control-B or whatever to get somewhere useful.

(The same error occurs if I set Lisp-Mode-Hook to #'COM-ELECTRIC-SHIFT-LOCK-MODE.)

I got rid of the *NUMERIC-ARG-P* error by changing my init file to read:

  (setq zwei:lisp-mode-hook #'(lambda () (zwei:turn-on-mode 'zwei:return-indents-mode)))

(the new code being inspired by the text of the function
ZWEI:ELECTRIC-SHIFT-LOCK-IF-APPROPRIATE)

but I still get the two BUFFERs-1.  (Ditto with other modes.)