The Google Chrome downloader gives this regular Installer Error on Windows more often than not. It seems the Chrome installer file is broken. One workaround to this problem is to try installing the Chrome from the file that gets downloaded if you click click here to retry link hyperlink in the Thank you for downloading chrome page that comes after downloading the first (broken) installer. This worked for me!
The offline Google Chrome installers can be downloaded from the following links. These links always download the newest version of Chrome.
Google Chrome for your own user account:
Google Chrome for all user accounts: