[Bug-AUCTeX] 11.85; problems with nil in load-path

[Art Werschulz]

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------------------------------------------------------------------------

I am using a ~/.emacs file consisting of
  (add-to-list 'load-path nil)

When I visit any TeX file, the modeline shows "Fundamental" mode.
(This also happens when I am creating a new TeX file.)  However, the
expected AUCTeX menus (LaTeX, command) appear in the menu bar, and the
key bindings are what one would expect from AUCTeX.

If I issue the command
  M-x tex-mode
the minibuffer reports
  Wrong type argument: stringp, nil

Note that if I have 
  (setq debug-on-error t)
in my ~/.emacs file, I get the following Backtrace when I first visit a TeX 
file: 

------%<--%<--%<---cut here---%<--%<--%<----------------------------
Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  directory-file-name(nil)
  #[(x) "ÁÂ!!݅  mapcar(#[(x) "ÁÂ!!݅  byte-code("ÂÃÄÅ\"\"       C¤‡" 
[load-path data-directory delq nil mapcar #[(x) "ÁÂ!!݅  (defvar 
toolbarx-image-path (byte-code "ÂÃÄÅ\"\"      C¤‡" [load-path data-directory 
delq nil mapcar #[... "ÁÂ!!݅  require(toolbar-x)
  byte-code("ÀÁ!ˆÀÂ!ˆÀÃ!ˆÀÄ!‡" [require custom toolbar-x tex-buf latex] 2)
  LaTeX-install-toolbar()
  LaTeX-maybe-install-toolbar()
  latex-mode()
  tex-mode()
  call-interactively(tex-mode)
  execute-extended-command(nil)
  call-interactively(execute-extended-command)
------%<--%<--%<---cut here---%<--%<--%<----------------------------

Please look into this.  Thank you very much!!

Emacs  : GNU Emacs 22.2.1 (i386-redhat-linux-gnu, GTK+ Version 2.12.9)
 of 2008-05-23 on xenbuilder4.fedora.phx.redhat.com
Package: 11.85

current state:
==============
(setq
 AUCTeX-date "2008-02-10"
 window-system 'x
 LaTeX-version "2e"
 TeX-style-path '("style" "auto" "/usr/share/emacs/site-lisp/auctex/style"
                  "/var/auctex")
 TeX-auto-save nil
 TeX-parse-self nil
 TeX-master t
 TeX-command-list '(("TeX" "%(PDF)%(tex) %`%S%(PDFout)%(mode)%' %t"
                     TeX-run-TeX nil
                     (plain-tex-mode ams-tex-mode texinfo-mode) :help
                     "Run plain TeX")
                    ("LaTeX" "%`%l%(mode)%' %t" TeX-run-TeX nil
                     (latex-mode doctex-mode) :help "Run LaTeX")
                    ("Makeinfo" "makeinfo %t" TeX-run-compile nil
                     (texinfo-mode) :help "Run Makeinfo with Info output")
                    ("Makeinfo HTML" "makeinfo --html %t" TeX-run-compile nil
                     (texinfo-mode) :help "Run Makeinfo with HTML output")
                    ("AmSTeX" "%(PDF)amstex %`%S%(PDFout)%(mode)%' %t"
                     TeX-run-TeX nil (ams-tex-mode) :help "Run AMSTeX")
                    ("ConTeXt" "texexec --once --texutil %(execopts)%t"
                     TeX-run-TeX nil (context-mode) :help "Run ConTeXt once")
                    ("ConTeXt Full" "texexec %(execopts)%t" TeX-run-TeX nil
                     (context-mode) :help "Run ConTeXt until completion")
                    ("BibTeX" "bibtex %s" TeX-run-BibTeX nil t :help
                     "Run BibTeX")
                    ("View" "%V" TeX-run-discard t t :help "Run Viewer")
                    ("Print" "%p" TeX-run-command t t :help "Print the file")
                    ("Queue" "%q" TeX-run-background nil t :help
                     "View the printer queue" :visible TeX-queue-command)
                    ("File" "%(o?)dvips %d -o %f " TeX-run-command t t :help
                     "Generate PostScript file")
                    ("Index" "makeindex %s" TeX-run-command nil t :help
                     "Create index file")
                    ("Check" "lacheck %s" TeX-run-compile nil (latex-mode)
                     :help "Check LaTeX file for correctness")
                    ("Spell" "(TeX-ispell-document \"\")" TeX-run-function nil
                     t :help "Spell-check the document")
                    ("Clean" "TeX-clean" TeX-run-function nil t :help
                     "Delete generated intermediate files")
                    ("Clean All" "(TeX-clean t)" TeX-run-function nil t :help
                     "Delete generated intermediate and output files")
                    ("Other" "" TeX-run-command t t :help
                     "Run an arbitrary command")
                    )
 )