Acrobat 6 wrong date in converted doc

We use Acrobat pro 6.0 to send proofs of converted document from a specialized third party software. Each page of the PDF document has a header with the date and time. The problem is the time printed in the PDF is 3 hours earlier than the current eastern standard time. Before Daylight savings time, the time was 4 hours off. Our software vendor says the problem has nothing to do with their software. It happens with different computers and the system time is correct. All systems use XP.

Does anyone have an idea where Acrobat is getting the date from and how to correct it?

Thanks