in reply to Perl modules and the GPL
The author of this module listed a copyright date as of 2002 and nothing about the GPL and he uploaded it to CPAN. Given that everyone understands to place it CPAN means that it will be distributed to CPAN source nodes, he was OK with that method of distribution.
As for whether you can distribute it yourself on a CD, well, that is something else. The reason is that the author could never change his mind and stop distributing it. At least with CPAN, if he wishes, he can turn around and say that this is no longer accessible(whether this is practical is an exercise for the reader...).
As Corion pointed out, perhaps you would be better off reimplementing the module on your own since it is fairly small and would be easier to do than argue with a bunch of lawyers.
As for dual licensing, it allows a customer who wants code changed and does not want those changes distributed (for whatever reason). The dual license gives the author a private version for clients and a public version(GPL) for everyone else.