Burning Vista Recovery Disc ISO file onto CD/DVD.

It is not a .rar file.
It's an .ISO
Your system is probably set to "suppress known file types" in folder options, and you've allowed WinRAR to grab the ISO file association and misrepresent it.
Go back to the downloaded file.
Don't process it in any way.
Burn it to a CD with an ISO-burner, like Imgburn, which is free, and works. (Vista won't burn ISOs)