back trace In unknown file

[Aaron]

Hi I am trying to parse a lilypond file and get the following error.




Backtrace:
In unknown file:
   ?: 0* [#<procedure #f (lyric)> #<Music SequentialMusic>]
In /disks/hda2/bakup/projectnigun/notation/norai/lily/ly/withwords.ly:
  16: 1* [text-map #<procedure #f (word)> #<Music SequentialMusic>]
   2: 2  (let (# # #) (if # #) (if # #) ...)
   2: 3* (ly:get-mus-property music (quote text))

/disks/hda2/bakup/projectnigun/notation/norai/lily/ly/withwords.ly:2:15:
In expression (ly:get-mus-property music (quote text)):
/disks/hda2/bakup/projectnigun/notation/norai/lily/ly/withwords.ly:2:15:
Unbound variable: ly:get-mus-property

What is missing and where do I find it?
thanks