After enquiring on perl.misc I decided to send an email to the author (Daniel Brian) who promptly replied.

The POD appears to have a typo so that..

should be ...

This example code given in the POD will now work with all types of sentences. It won't spit back any results for sentences with null linked words. To parse these you need to use the $parser->opts and change 'max_null_count'. Look in the '/scripts/parse.pl' for an example of how to do this and don't make the newbie mistake that I did and not look at all the files and dirs in the tarball.

Thanks to Dan for the prompt reply.