Don't use this module. It has an overloaded API, which uses global variables. Look at Net::IDN::Punycode and Net::IDN::Encode instead.
(NB: I'm the current maintainer.)
In reply to previous reviewer:
it looks like this module is integrated into Net::IDN::Punycode. Maybe it's fixed there?
critical bug, but no patched yet for over 2 years.