Orders page shows random purchase date

In orders page, the purchase date is random for every order ie todays date is 17 March 2010 but it gives 20 June 2011 instead.

When I change the order status to processing the customer is notified. And then customers become confused as the date of the purchase is wrong.

Does anyone know how to fix it?
Cheers

I think that it has to do something with the date format...