the problem with downloading the file off the net is that you may hose your system - are you sure that came from a Vista Home Premium ***x64*** ?
Are you sure the file is legitimate? Not a virus?
I honestly recommend that you do not do that again.
Try the steps outlined in
Windows Media Player 11 cannot play DRM-protected content on Windows Vista and see if it helps.
Now, as to the file not being repaired and being corrupted: