Lilypond inside scheme

[Joe Neeman]

In lilypond 2.6.3, I copied the example from the manual page on "Using Lilypond 
syntax inside scheme":

#(define mynotes #{ \override Stem #'thickness = #4
                   { c'8 d' } #})

But it gives me the error
Parsing...
<string>:1:22: error: syntax error, unexpected STRING
                   {
                     c'8 d' }  }

Is the example incorrect or have I done something wrong?

Thanks,
Joe