Installed the latest versions following your instructions. No more FSX crashes.
THANKS!
Just to make sure I hadn't done anything stupid before, I then tried "f" again and it worked. I tried "t" again and the crashes came back. I'm now running the newest release.
Leads me to believe something in "t" had conflicted with FSX-A running on Windows 8.1 but whatever you changed in the code afterwards removed the conflict.
By FSX-A I mean Acceleration.
By the way, the Add-on Menu crash did happen only with "t", for example when doing drop down to find FSUIPC or move to [sDK] Tools memu, but did not happen with any other version installed or no FSUIPC installed, from which I can only conclude that, no matter how far-fetched it may sound, the "t" install was something to do with the phenomenon. It may have been related to my FSX install (or other add-ons in combination with "t" alone). I cannot imagine how or why.
Thanks for the help and for your dedication to an indispensable piece of software for FSX users everywhere.
ian