If you are using Windows Vista / Windows 7 and get an endless loop when upgrading your game version this might be something that will help you.
A problem that will end in an endless download loop is when you don't have the rights to write the downloaded installer to disk. This occurs when the installer is executed in the Windows Compatibility mode.
Normally Windows Vista / Windows 7 will install the game into the Program Files folder and user data to the users AppData\Roaming folder. The later one is important because Windows Vista / Windows 7 will not allow programs to write files do the Program Files folder. So when the game get the notification that a new version is online it downloads it automatically and stores the installer in the Save folder of your game. For that the Save folder must be in the users AppData\Roaming folder.
When the installer is launched in the Windows Compatibility mode then the install path and the data path is the same ( This is for Windows XP and previous versions ). For Windows XP and previous versions this works fine because programs were allowed to store data in the Program Files folder. But since Windows Vista this isn't allowed anymore and that's what's causing the endless loop on Windows Vista / Windows 7. The game is downloading a new version and wants to store the installer in the games Save folder but Windows doesn't allow this and so the installer is not stored.
Resolution: Uninstall the game and download the installer manually from the member area and install it.