The only workaround(?)you are willing to propose should be an access via TeamViewer to my PC. Really unsual, isn't it? I bought a piece of furniture from you and now you want to have the keys of the house..after damaging it with changes only announced on a "private" forum and not by mail as other companies do.
You are getting it backwards: it's NOT the "Addon Manager that kills FSX", is something else you have put in your FSX that did it, and the reason why it must be dealt in private, will be obvious to you after we'll connect.
And no, nobody is getting any "keys to your house", you should check how TM works, because nobody can access your system if you don't launch TM, and the password is randomly selected and changes at *each* start of the software so, after that one connection (which is made in YOUR presence), it will not possible to ever connect to you again, unless you start TM again and supply again the new password for the session.
A working fix would have been a minimum to respect people how paid you for your software.
There's nothing to "fix", since the software is working and the only fix needed is acting on your system to remove the OTHER non-FSDT files that are causing this.
Or at least some explanations about what you want to do and to access on the remote computer.
Explanations of why this should be dealt with privately, have been provided to all those that sent the PM about the connection, as requested.