cd-r 99 minutes

Hi first post .
I have an mp3 that wont fit onto the standard
80mins cd-r so just purchased some 870meg 99 minute ones .
The problem is when i go to burning the file in nero
it says there is not enough space on the medium and wont let me do it .
Also when i check the medium in the drive through nero it says its 79meg .
What could be the problem here ?

Thanks coll .

 

Found my answer .

http://lib1.store.vip.sc5.yahoo.com/lib/precisioncddvd/99info.html