What do mean by "it works properly on those"? Dates should be displayed according to your Windows Regional settings (as set in Control Panel), and this has no bearing on how the dates are stored in the database. When a date is added or changed, it should be handled according to your Regional date setting as well. So if that's "d-m-yyyy," then entering today's date as "16/9" should result in "16-9-2009." Entering "9/16" should be ignored because it's invalid.
Are you saying the date for existing movies is displayed as "d-m-yyyy," but that for new movies is "m-d-yyyy"? If so, something is seriously wrong.