clone dvd doesn't recognize media!

i’m using dvd-r, verbatim

Be more specific.First exit any program and load a blank dvd in your burner and wait for a popup window about a blank dvd.If you see it Windows works ok and so the burner.If not check your burner compatibility and start from there.Here is a link to find out,type the name of your burner and press search. http://www.videohelp.com/dvdwriters.php?DVDname=Plextor&Submit=Search&cdrs=&cdrws=&dvdrs=&dvdrws=&dvdrsdl=&dvdprs=&dvdprws=&dvdprsdl=&dvdrams=&buffer=Any&cdrom=&dvdrom=&orderby=Name&hits=25&Search=Search&country=