I also had this problem but with 2 1.5tb seagate drives. Go to dlinks site and download the 1.01 firmware and you will see that you most likely never had a problem, the progress count was just always wrong. Originally the progress would immediately shoot up to 94% and never go further. If you waited long enough it would have eventually finished but with the new firmware the progress was measured accurately.
Here is the link to the page with the firmware.
http://support.dlink.com/products/view.asp?productid=DNS%2D321#
If however you already have the update, then I suppose I just wasted your time by having you read this. Hopefully this will do the trick though.