I have had a problem with mine as well. America/Chicago timezone. I modified Chicago.ics and it worked. There is an update timezones patch in gnome-bug #301363 that needed to be upstream (submitted) to Ubuntu Dapper & Edgy updates.
Thanks. -- Daylight Saving changes in Western Australia https://launchpad.net/bugs/79323 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
