Nero sync and burn errors!

Ive been having LOADS of issues burning with nv4 (i have Nero 7?) which i thought was down to either the media or the burner so as a final test i burnt an image of what i had previously tried to get on a dvd+r (Verbatim azo) to my hdd.I then mounted this image and played the results which were just as out of sync as the dvd burns were???Thus my theory about the dvd/burner cant be right,can it?Sometimes i get an error as soon as its time for the image to be physically burnt and like i said,Nero will completely finish and state success but again on playback MAJOR sync issues!
Ive also had cause: 129 (neroapi_call_failed) floating about.Could someone please help me i have wasted probably a tenner on disks! Plus i look foolish having given a friend a film they now think im incapable!!!
Cheers.