nero express 6.3.1.23b asks for dvd - r??? to burn on

I haven't used this program much, though it did come with my BenQ 162I external burner.
I went to copy a disc and when I put in a Maxell r+, a Sony r+, tdk r+ as well as an imation r+ which is the media that the BenQ support out of Irvine Ca. advise me has been tested and are the media to use; the message requesting a DVD R- flashed on the screen.

I don't understand this as we use the same BenQ 162I dual layer burner 16X which we bought last december on my better half's toshiba notebook and as well my son's notebook and they are all the same model of notebooks.
We have no problems and burn backups fine with no coasters out of over 100 that we have used any of the above r+ media. The better half uses One Click DVD Copy on her unit and the son uses Sly softs Clone DVD and of course both use Any DVD, all purchased versions for their own computers.

I also have a purchased version of Any DVD on my notebook.

My neighbour and I were talking about this and he was wondering if perhaps there is a setting or option on Nero that I have to set in order to burn on an r=.

I should say that my source was an r- dvd, a family home video from our mini dv camcorder.

We burned backups of this same r- on the One Click DVD Copy on the better halfs with the same burner and then also on my son's with Slysofts Clone DVD.

Does anyone have any ideas what could be the issue with my use of Nero?
As I said I never have tried it before and the first time I do, I run into this problem.

I hope someone has some experienced suggestions, thankyou.
Best Regards,