The following is copied from a ticket I submitted in which I was told they could not help me and to post to the tech support forum to see if one of you had an answer.

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Let me make another stab at this. When adding a new DVD (or modifying an old one), today's date is automatically placed in the Purchase Date of the Personalize DVD dialog. The date format displayed is  DD/MM/YYYY. When you click on the calendar to change it, it brings up the correct month with the correct day highlighted. If the day you are changing to is 1-12, everything works fine. If is is 13-31, DD/01/2009 is displayed where DD is the month you attempted to change to. It's clearly mixed up on the date formated since, even if the application were using DD/MM/YYYY the Calendar control appears to be giving the application back a date that is MM/DD/YYYY, the application considers the month invalid (since the month is really being interpreted from what the day is and is not a valid month when the day is more than 12) and reverts the month back to January.

I've updated to 3.5.1. I've re-booted. I've re-installed. I checked the date format under Regional and Language options in Control Panel. Checked Profile Options "Defaults" tab, Locality is and always set to United States. "System" tab, Localization Language is English and Currency US. There's no place to set the date format used that I can find and I think Profiler inherits that from the system.

I installed it on another computer and tested it before the database was restored. The date worked OK. I restored the database to the new install. The date was OK. The problem is not in the database (just covering all bases, it seemed unlikely it would be).

I corrected some dates and backed up the database using this new install on a different computer. I then restored the database from what the new install backed up on the computer that was giving me trouble and it is still giving me trouble :^( .

If I want to have accurate purchase dates, it looks like I have two options: Only purchase DVD's on the 1 to the 12 of any month; Use the other computer to do all the updates (although this is not my computer, it is on my network).

Oh yes, I guess I could also wipe and load my computer and re-install every app I have installed. Probably a 6 hour job.

Maybe you could try going back to control panel Date Format and Reset customizations, save and perhaps even reboot. Sometimes the registry gets messed up in subtle ways that you can fix by just resetting something explicitly, even though it appears to be set already.