Just wanted to mention thanks for helping with the list of suggestions you had tried. That got me going in the right direction.
Some things I encountered with 1.67 Monkey, FBV MKII Shortboard and Spider IV amp (those devices were already correctly registered on the LIne 6 website with my login):
1) The Monkey software didn't appear to be able to work properly when the computer is behind a proxy server (couldn't find the Line 6 servers over the Internet in order to check for files). I removed the proxy from the equation and The Monkey found the Line 6 servers over the Internet.
2) As suggested above, after The Monkey couldn't find my FBV MKII Shortboard, I restarted the computer and then started up The Monkey without anything attached to the USB ports. Then after the app was up and I chose whatever the default device was to get the app running, I then plugged in the USB cable from the FBV MKII Shortboard (which had the LIne 6 Spider IV amp behind it), hit the "Connect to device" on-screen button and vi-ola, my FBV MKII Shortboard and the Spider IV amp behind the FBV MKII Shortboard were then found right away. Seems you have to have the USB cable unplugged from the computer each time when The Monkey app is started up, then plug in the USB cable to the computer from the FBV MKII Shortboard so The Monkey can find it and the amp behind the Shortboard
The updates to the firmware for the Spider IV as well as the FBV MKII Shortboard went fine after that. It did, however, require a reboot of the computer and a restart of The Monkey app without the USB cable attached followed by a re-connection to the computer of the USB cable from the FBV MKII Shortboard in order to see the updated versions of the firmware on the FBV MKII Shortboard and the updated version of the firmware on the Spider IV amp.
Hope this helps others.
Datto