There are no problems whatsoever with the update but, of course, if too many people are downloading and the same time, the download speed will obviously suffer, and it's possible you might have mixed up files, which might be the CAUSE of the problems.
But since the installer is brand new, it's not strictly necessary to have it *download* the Addon Manager so, once you got the installer, if you disable the network while installing, it will say there's no connection, and will ask if you want to continue using local files. Allow it, and the installation will proceed offline.