Problem with dates in Outlook Express 6

Hi All

This is my first post so pls let me know if its not in the right thread.

I am using Outlook Express 6 and have noticed that some emails I have sent last month have the wrong 'sent' date on them. More specifically, the date is in the future which hasn't happened yet. For example, I sent an email last month which shows a sent date of 28 May.

Any ideas why and how I can correct the date?

Note that the date and time is correct on the computers internal clock. I have not had the computer restored or updated etc

Thanks

Sitbon