If you read the comments attached to that post you would see that those links haven't worked for over a year. In fact, I believe that MS doesn't use Digital River anymore. Try Google.........I'm sure there are several rapid shares or torrents that you could use....
If your computer came with 32-bit Vista you can order the media for the 64-bit version (of the same edition) from M$ for a nominal charge for shipping. You have to provide your original product key when ordering. Actually I don't remember if it is was for oem or retail versions that they do this but it's worth checking.
To my knowledge, I don't think they will do it for OEM (when I attempted to use the OEM product key for ordering, it failed). So it seems like my only option is to find another way to download the anytime upgrade disk files. Unfortunately, I haven't had such great experiences with torrents in the past though.