I received a reply that I need to produce a _gen.Mission file????? or the dev's wouldn't do anything.
And so you quickly concluded that the RoF forum is not welcome for bug reporting ...

Any forum search, or further questioning about _gen.Mission, would have told you this: that when you fly a career mission, inside your mission folder RoF generates a _gen.Mission file, which will be overwritten by another one when you advance to another career mission. The devs would need such _gen.Mission file, when you have a mission error, to *see* what was the exact problem. So the best help you can give them in such cases is to describe the error and attach that 'culprit' _gen.Mission file.
A nice side effect - if you like a particular career mission, you can save that _gen.Mission by opening it in Mission Editor and renaming/resaving it (and of course, you can edit it if you want).