Problem with imgburned GOW2 backup-- Converts to DVD

I wanted to make a backup for my Gears 2 disc, and so, after getting the required files onto my laptop, attempted to burn them onto a Verbatim DVD+R DL disc using first Xbox Backup Creator and then, that failing, ImgBurn.

My problem was that both programs burned the files (a .iso and a .dvd) onto the discs as DVDs-- my 360 didn't recognize them to be games and played them as DVDs. The image that showed on the screen said something to the effect of "Please insert into an xbox 360"

Could the problem be the hardware-- my dvd burner? It was factory installed and says on the side basically that it is dvd read/writable, but nothing about dl. Also, if something specifically needs to be done to my 360, I haven't done that either.

Any help would be appreciated-- thanks.

M4ss1v3