Support has a patch available for current and older versions of VW - and Alan Lovejoy has helpfully posted a comprehensive answer as well, which I quote nearly in full here:

One way to make the necessary change is to evaluate the following "do it" (which is correct for Pacific Time):

TimeZone 
    setDefaultTimeZone: 
        (TimeZone 
            timeDifference: -8 "Pacific Time"
            DST: 1 at: 2
            from: 73 "Second Sunday of March"
            to: 311 "First Sunday of November"
            startDay: #Sunday).

Instead of the "timeDifference: -8" which is correct for Pacific Time, Mountain Time has a time difference of -7 hours, Central Time has a time difference of -6 hours, and Eastern Time has a time difference of -5 hours. Arizona is the big exception, since it does not observe daylight saving time (but Navajo reservations in Arizona do observe DST!) The Arizona rules haven't changed.

Another way to get the correct rules is to install the TimeZone-External Repository-Olson TZDB package, which can be downloaded from the Chronos web site, or simply by clicking on the following link: TimeZone-External Repository-Olson TZDB (read and follow the installation instructions.)

Once the TimeZone-External Repository-Olson TZDB package has been installed (according to the instructions,) evaluating one of the following "do its" will update "Core.TimeZone default" with the correct rules:

 (TimeZone at: 'America/New_York') beReference
 (TimeZone at: 'America/Indiana/Indianapolis') beReference
 (TimeZone at: 'America/Chicago') beReference
 (TimeZone at: 'America/Denver') beReference
 (TimeZone at: 'America/Boise') beReference
 (TimeZone at: 'America/Phoenix') beReference
 (TimeZone at: 'America/Los_Angeles') beReference 
 (TimeZone at: 'America/Nome') beReference
 (TimeZone at: 'America/Adak') beReference
 (TimeZone at: 'Pacific/Honolulu') beReference

Yet another way to get the correct time zone rules is to install Chronos.

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