|Does this also happen, when you write it to a CD/DVD image?|
If not, you can download and install tools like DAEMON-Tools for free, mount this image file, created by nero to DAEMON-Tools and check, whether the image is working.
If it is working, it should also work, when you burn this image to CD/DVD.
The original poster should always write the last response !!!
Let us know, if the problem is solved !!!