Sony dvd rw Q58a won't burn dvd

Hi, I’m Polly i was wondering if someone could tell me how to get this to burn dvds.This is a friends computer
and he is useing a Sony Q58a it will burn cds fine but when i tried to burn a dvd it said i needed the dvd-r not the dvd+r i was useing, so i bought what it said to use, I than tried again and it burned about half way and failed. The computer has Nero 6, dvd shrink, sonic, i do not understand why it will not pick up the dvd+r disk. Can someone please help me with both promlems.
Thanks, Polly

Please post more info about the Nero 6 version used, the media brand and its rating and maybe a logfile from Nero if possible.