In Nero there will be an option to create a cd from an Image as opposed to making a plain old "Data cd". I'm afraid you did the latter and this is a common mistake by folks who haven't really dealt with disc images before. Depending on whether you are using Nero, Nero Express , or the Nero gui frontend, the option to do it is in a different place. If need be, check the 'Help' in Nero. I'm sure they have a section dedicated on the proper way to burn ISO and other cd image formats.
-Tharin Olsen
