To make the files in the
writable you need to give “Write” access to the Internet Guest Account
IUSR_computername) or the appropriate web server group
IIS_WPG). This is done
through the right-click context menu on folders and files chosing “Properties”
and selecting the “security” tab.
Upgrade packages are zipped in a .tgz format so you can download 7zip to unzip it.