Read Re^2: Impact of U.S. Daylight Savings Time changes in 2007 on Perl distribution/code from January 2007 and pay attention to Dave Rolsky's explanation of how he updates DateTime::TimeZone each time a new version of the Olson tz database is released. Also, take a look at the Changes file for DateTime::TimeZone.

Dave does a good job of keeping DateTime::TimeZone up-to-date with the Olson tz database. You need to do an equally good job of keeping your Perl installation up-to-date with the DateTime::TimeZone CPAN module. Consider subscribing to the mailing list datetime@perl.org.

Jim