Firstly, I've found that paver block driveways need to be sealed every year... But, try some mineral spirits. You can get a half gallon or so from your favorite DIY store, usually in the paint section since it's often used to clean brushes. Since it's not petroleum based it will not add to your unsightly stain. Pour a generous amount on the stains and cover with several layers of loosely shuffled newpaper. This will soak up the fluid and the stain along with it. Next, to completely remove the stain, rent, borrow or buy a pressure washer. Use the attachment device for soap or deck cleaner and spray generously and rinse with the high pressure... Not as difficult as I've made it sound...