I followed the following method provided by Ade and could install it without going online. "You should be able to copy the full Pro Pinball directory across and the new exe, then copy UserDefault.xml from your user's AppData\Local\ProPinball directory to the corresponding directory on the cabinet. That should make the game see you as signed in and find the graphics data."
One problem is that I can't install the 1920 resolution pack on my desktop - probably because the on-board GPU doesn't provide this.
I could download 1800 (and 2160) and it is possible to play but I assume 1920 will improve the image quality..
Tried downloading the package directly : http://download.pro-pinball.com/ultra/g ... 0_1920.zip
extracted the zip in /ProPinballUltra/extra_data/timeshock/low/ and copied the
"installed" file from the 1800_1800_4096 directory.
The 1900 resolution is then available in the graphics menu but the program hangs in 'loading' step after trying to play the table.