You may see systems that have successfully applied the Windows DST2007 hotfix 931836 but are still operating on old DST rules after March 11. Opening the Time/Date control panel applet and changing the time zone to a new time zone; hitting apply, and changing it back to the original time zone will often correct this problem.
Another variation of this problem has been observed on Windows 2000. In that scenario after applying the DST hotfix or using TZEdit and then changing the time zone (manually or with the script above), the time zone still does not update. For that situation we’ve found that making the registry updates described in 914387 followed by running the script above will reliably cause the system to follow the new DST2007 rules. A symptom you may observe is that if you set the clock to the correct time, it will revert back to the incorrect time within one hour.