[OS X Emacs] Wiki code not working: Symbol's function

[Marius Hofert]

Dear Win,

thanks a lot for your help. I changed the code accordingly. On starting Aquamacs, I obtain:

Loading prestart plugin files ...
... done.
Shell: /bin/bash
Loading `emulate-mac-keyboard-mode': old-style backquotes detected!
Loading /Users/mhofert/Library/Preferences/Aquamacs Emacs/Recent Files.el (source)...done
Cleaning up the recentf list...
25 environment variables imported from login shell (/bin/bash).
Loading /Applications/Aquamacs.app/Contents/Resources/lisp/aquamacs/edit-modes/auctex.el (source)...done
Loading plugins ...
Loading /Applications/Aquamacs.app/Contents/Resources/lisp/aquamacs/site-start.el (source)...done
... done.
Loading /Users/mhofert/Library/Preferences/Aquamacs Emacs/customizations.el (source)...done
Loading /Users/mhofert/Library/Preferences/Aquamacs Emacs/Preferences.el (source)...


An error has occurred while loading `~/Library/Preferences/Aquamacs Emacs/Preferences.el (or .elc)':

Wrong type argument: stringp, nil

To ensure normal operation, you should investigate and remove the
cause of the error in your initialization file.  Start Emacs with
the `--debug-init' option to view a complete error backtrace.

Mark set
one-buffer-one-frame-mode disabled.
Mark set
Loading /Users/mhofert/Library/Preferences/Aquamacs Emacs/frame-positions.el (source)...done
Mark set [5 times]
Aquamacs is based on GNU Emacs, a part of the GNU/Linux system. It is Free Software: you can improve and redistribute it under the GNU General Public License, version 3 or later. Copyright (C) 2011 Free Software Foundation, Inc. (C) 2011 D. Reitter. No Warranty.
Mark set [2 times]
No connection file "/var/folders/9V/9Ve4N9CNG405i-blJ8CN8k+++TI/-Tmp-/emacs501/server"
Automatic display of crossref information was turned on
Applying style hooks...
Loading /Applications/Aquamacs.app/Contents/Resources/lisp/aquamacs/edit-modes/auctex/style/book.elc...done
Applying style hooks... done
Mark set [2 times]
Applying style hooks...
...

Do you see what's going on? 

Cheers,

Marius