[AUCTeX] Symbol's function definition is void: nil

[Alad Wenter]

Hi,

I have installed AUCTeX on emacs-25.2-x86_64, emacs-25-x86_64-deps and Windows 
7 using GNU ELPA. (I don't use emacs 25.3 due to a DLL issue: [1]) 

When trying to Generate previews, I get a "Symbol's function definition is 
void: nil" error. I've set the TeX engine to luatex with the TeX-engine-set 
command.

Toggling debug-on-error results in the following output: (I replaced the file 
names with ## in the output)

Debugger entered--Lisp error: (void-function nil)
  nil(nil t)
  apply(nil (nil t))
  (concat (and (stringp TeX-command-pos) TeX-command-pos) (apply (function nil) 
args) (and (stringp TeX-command-pos) TeX-command-pos))
  (shell-quote-argument (concat (and (stringp TeX-command-pos) TeX-command-pos) 
(apply (function nil) args) (and (stringp TeX-command-pos) TeX-command-pos)))
  (lambda (&rest args) (shell-quote-argument (concat (and (stringp 
TeX-command-pos) TeX-command-pos) (apply (function nil) args) (and (stringp 
TeX-command-pos) TeX-command-pos))))(nil t)
  apply((lambda (&rest args) (shell-quote-argument (concat (and (stringp 
TeX-command-pos) TeX-command-pos) (apply (function nil) args) (and (stringp 
TeX-command-pos) TeX-command-pos)))) (nil t))
  TeX-command-expand("%(latex)" nil)
  TeX-inline-preview-internal("lualatex --jobname=\"_region_\"  
-file-line-error   
\"\\nonstopmode\\nofiles\\PassOptionsToPackage{active,tightpage,auctex}{preview}\\AtBeginDocument{\\ifx\\ifPreview\\undefined\\RequirePackage[displaymath,floats,graphics,textmath,sections,footnotes]{preview}[2004/11/05]\\fi}\"
 \"\\input\" \"_region_.tex\"" "_region_" (TeX-region-file . "_region_") 
#<buffer ##.tex> ("##" "lualatex -ini -interaction=nonstopmode \"&lualatex\" 
\"prv_##\".ini    
\"\\nonstopmode\\nofiles\\PassOptionsToPackage{active,tightpage,auctex}{preview}\\AtBeginDocument{\\ifx\\ifPreview\\undefined\\RequirePackage[displaymath,floats,graphics,textmath,sections,footnotes]{preview}[2004/11/05]\\fi}\"
 \"\\input\" \"##.tex\"" . #<overlay from 1 to 55 in ##.tex>) "##" ((lambda nil 
(/ 10.2 (preview-document-pt))) (72.05673758865248 . 71.88679245283019) [nil 
nil nil nil]))
  preview-generate-preview(t "_region_" "lualatex --jobname=\"_region_\"  
-file-line-error   
\"\\nonstopmode\\nofiles\\PassOptionsToPackage{active,tightpage,auctex}{preview}\\AtBeginDocument{\\ifx\\ifPreview\\undefined\\RequirePackage[displaymath,floats,graphics,textmath,sections,footnotes]{preview}[2004/11/05]\\fi}\"
 \"\\input\" \"_region_.tex\"")
  preview-region(1 9393)
  preview-at-point()
  funcall-interactively(preview-at-point)
  call-interactively(preview-at-point nil nil)
  command-execute(preview-at-point)

My .emacs file:

;; Added by Package.el.  This must come before configurations of
;; installed packages.  Don't delete this line.  If you don't want it,
;; just comment it out by adding a semicolon to the start of the line.
;; You may delete these explanatory comments.
(package-initialize)

(put 'downcase-region 'disabled nil)
(put 'dired-find-alternate-file 'disabled nil)
(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(package-selected-packages (quote (ada-mode auctex))))
(custom-set-faces
 ;; custom-set-faces was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 )

My .emacs.d folder is empty apart from elpa, auto-save-list and a bookarks 
file. I have no other packages installed apart from AUCTeX. How can I 
troubleshoot this issue?

Best,
Alad

[1] 
http://gnu.emacs.help.narkive.com/4kg9yq1P/unable-to-run-64-bit-gnu-emacs-25-3-on-windows-7-professional-service-pack-1