Order record keeping - Date 1 day ahead!

[shopsecure]

Our shop sets the dates of initial signup and order by 1 day (plus change) in the future throughout the back-end, on order and customer tracking. So far we were unable to locate (or resolve) the issue.

Checked:
The server date/time is ok, prestashop time zone is set correctly. Other Websites (non-presta like drupal or custom back-ends) we run on the same server apply the correct date and time. That's pretty annoying when an order is placed tomorrow and the order prep date is today. Same problem with the customer signup, we have some who signed up tomorrow. Same problem with the connection date/timestamp under customers listing 2010-12-10 03:22:29 while the actual server date/time is 2010-12-09 17:43:xx
How weird is that?

Has anyone experienced the same issue?
Thanks for any help in advance.

Ver: 1.3.3.0 win/iis6/php5/mysql5
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