Nero star smart says not enough space on disk even on overburn

I have been trying to burn dvd’s and I have everything I need. It works fine until I get to the point where I insert the new disc and it tells me that I haven’t enough time on the disk, even though I have it set to overburn. Is there some sort of setting I need to use?

Update Nero from here:http://www.nero.com/us/nero-up.php and when you open the Nero StartSmart be sure the switch on interface is set for dvd.Size up to 700 MB works on cd higher works on dvd.If you use Nero Vision at the bttm of the page is a scale with the size of your file so try to match it.

I am trying to burn a dvd from dvd shrink it encodes it then sends it to nero, it says to put in a blank dvd-rw. I put one in but it just keeps coming up with checking discs??? Is the a type of dvd-rw disc????

kaj si