Guile error starts occurring all of a sudden

[Patrick or Cynthia Karl]

I have been using the command(?) #(include-special-characters) all morning and 
yesterday.  Then all of a sudden I start getting this error:

Parsing...
/Users/pat/Documents/LilyPond/tmp/test_guile.ly:3:2: error: GUILE signaled an 
error for the 
                                                                                
                        expression beginning here
#
 (include-special-characters)
Unbound variable: include-special-characters

I get this error with the following lilypond file, called test_guile.ly:

        \version "2.18.2"

        #(include-special-characters)

Ordinarily, I run jEdit, but I also get the error when running lilypond from 
the command line:

$ lilypond -V test_guile.ly
Log level set to 287
GNU LilyPond 2.18.2
.
.
.
Using `nederlands' note names...
 [test_guile.lyBacktrace:
In unknown file:
   ?:  0* [lilypond-main ("test_guile.ly")]
In 
/Applications/LilyPond.app/Contents/Resources/share/lilypond/current/scm/lily.scm:
 965:  1* (let* ((failed #)) (if (ly:get-option #) (begin #)) ...)
 965:  2* [lilypond-all ("test_guile.ly")]
 978:  3  (let* ((failed #) (separate-logs #) (ping-log #) ...) (gc) ...)
 990:  4* [for-each #<procedure #f (x)> ("test_guile.ly")]
In unknown file:
   ?:  5* [#<procedure #f (x)> "test_guile.ly"]
In 
/Applications/LilyPond.app/Contents/Resources/share/lilypond/current/scm/lily.scm:
 992:  6* (let* (# # #) (if separate-logs #) (if ping-log #) ...)
1003:  7* [lilypond-file #<procedure #f (key failed-file)> "test_guile.ly"]
1038:  8  [catch ly-file-failed #<procedure #f ()> #<procedure #f (x . args)>]
In unknown file:
   ?:  9* [#<procedure #f ()>]
In 
/Applications/LilyPond.app/Contents/Resources/share/lilypond/current/scm/lily.scm:
1039: 10* [ly:parse-file "test_guile.ly"]
In test_guile.ly:
   3: 11* (include-special-characters)

test_guile.ly:3:1: In expression (include-special-characters):
test_guile.ly:3:1: Unbound variable: include-special-characters

My OS is OSX 10.7.5.

I ran Disk Utility (verify disk) on my hard disk (where /Applications lives) 
and got a clean bill-of-health.
When I first encountered the error, I was still running LilyPond 2.18.0, but I 
have downloaded and installed version 2.18.2 and still get the error.

Does anyone have any clue for me?