I asked Jon Griffin (
mailto:jon@jongriffin.com), the acs-reference porter, this a few days ago by email. He said that he had seperated timezones out of acs-reference b/c of its size. Jon's also improving it, but I don't know the details. It is currently checked in CVS at /openacs-4/packages/timezones, but I don't think it will help you in its current state.
I believe you can just comment this reference out for a quick workaround to your problem since it appears that the table is referenced in the calendar data model but never used.
