"XCT > Preferences > Desktop Installer Location" is where you change the URL that the XCT Landing page's "Install" button points to for the XPanel Desktop downloads.
By default it's set to:
You can always download them beforehand and toss them on the processor (\html\ folder) or local webserver and point it there before running the conversion.
Dave H - Crestron True Blue Tech Support Engineer Since 2014