If you look at your purchase receipt, you would know you can't "redownload" from our site, but you are supposed to download from Digital River.
The link lasts 30 days from purchase, or 2 years if you bought the optional Download Protection service ( which is enabled by default so, if you haven't bought it, it's because you chose not to ). If your link has expired, as explained in other post in the forum, you should contact support BY EMAIL, so we can send you the installer using other means.