I amn not sure if Nero has a md5 checked but if not try this
basically you should be able to open the third mentioned file and see the hash or the md5 sum....then use nero or the verifier file to check they are the same.
It is possible you have a bad download and the md5 will help.
forgive me if you have already understood that point but it was not clear to me if you had or not.
2) if both are the same, there may be an issue with nero....put the dvd into your windows system and check that the dvd shows more than one file....
if it only shows one file ....blah blah.iso....then you have not used nero to burn the dvd iso correctly....
if this is whats happened try using a dvdrw....and check the documents on how to burn an iso please