Sony DRU500AX Problems HELP

I have just bought the Sony DRU500AX, this is the problem… I can record on a DVD+R using Sony software no probs, if I put in a DVD-R it burns for 2 mins then spits it out saying there is some sort of fault. If I use Nero, it won’t record on either, just says something about blank media. I am using Bulkpaq DVD+R and DVD-R, also tried Datawrite DVD-R, these work no probs in a friends Sony DVDrewriter. WHAT AM I DOING WRONG???:confused:

What Software came with the DRU500AX is it still Record Now ?
I have the DRU500A & thats what came with mine. I’ve heard of people having probs with some versions of Nero & Record Now & their fix was upgrading Nero & then installing Record Now. I personally have both plus others & the drive takes what ever I throw at it. Hope this helps a little