Ok, it's a good idea (in fact, the only idea I have) to check the data and ime for your shared disk. I found the manual here
http://www.wdc.com/wdproducts/library/UM/ENG/4779-705058.pdf
Basically, you connect to the shared disk using one of the methods on page 54, and you will see the "Dashboard". There are date and time settings in the dashboard, see page 61-62. I have a theory that the shared disk has a clock 2 days slow, but that most software uses your computer's clock instead.