bad vista 64bit downloads

I have downloaded Vista 64 bit version 5 times all with the same result. When I try and use Nero MD5 Verifier in Windows XP Pro and the Vista 32bit I get the following error:
("Microsoft Visual C++ Runtime Library, Runtime Error! Program: G:\NeroMD5Verifier\Nero MD5 Verifier.exe This application has repuested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information.")
I can run Nero MD5 Verifier with the 32 bit version with no problems in both Windows XP and Vista 32bit.
I have tried twice to burn the 64 bit .iso file with the same results, after bootup with the dvd, I get a problem with some disk drive and that I should reboot, pick recover instulation and let Windows try and fix the problem, or something like that.