The physical file does not reside on the user club website. Instead you have to download the file from the official Roland Keyboard Club website. You find more information here:

http://www.rolandkeyboardclub.com/v/OS_updater_G70_2_01.php

Download the file using this hyperlink:

http://www.rolandkeyboardclub.com/upload_area/os_updater/g70/G70_Ver_02_02.sys