It is not possible to add CGMS/CSS/Macrovision to a burned DVD. Begin by removing it.
The rest may be a Nero problem- if you want to use an image as your source, you must tell Nero to burn from the image. This is a special command in the menu bar and not in their wizard. I don't have Nero in front of me, so I don't recall what menu it's in.
I always thought that an ISO created in Encore had to have it's extention renamed to "filename.NRG" (the filename.NRG is only an example)
And to burn an image using nero go to RECORDER>BURN IMAGE ( I use version 184.108.40.206)