Book tokens not working

I'm trying to use this module to generate the titles of the pages of a book as being 'Parent node title - value of a cck field'.
The '- [cckfieldvalue]' bits are fine. However, I can't get [book] or [bookpath] to do anything. The token is substituted with nothing rather than the parent title.
The node in question is definitely part of a book and has a parent, so I don't understand this behaviour.
As a test to see if the issue was in token I tried using pathauto and the [book-raw] & [bookpath-raw] tokens and the aliases are being generated fine, so that really only leaves this module.