It's very likely Outlook...
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Never mind this post. It helps to read all the posts before posting!

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I got this from the Corporate office:
In order to address time zone changes, this tool will help adjust calendar items in Outlook after the operating system has been updated with new time zone definitions. This tool should only be applied to those individuals that have there Calendar setup in there personal folder and have appointments that are affected by the time change on March 11. The users that have there calendar on the exchange server have already been updated. Make sure before you apply this tool that the updated time zone patch or work around has already been applied to the Operating System.
The tzmove.exe tool must be installed under an administrator account on the customer’s computer. After the application is installed login as the user and go to the following directory. Click on tzmove.exe to open the Change Calendar Time Zone Tool.
C:\Program Files\Microsoft Office\Office12\Office Outlook Time Zone Data Update Tool\TZMOVE.EXE
Once you have the tool open please change Data File to Personal Folders also change Original Time Zone to the Time Zone the customer is located in. Leave the other settings as default and click OK.
Let me know if you need the tool. I have it. It's 8MB so I can't post it here.