I don't know much either, but I answer to the extent I can.
Was there any problem with doubled objects check?
If there are doubled objects, the mission cannot be saved.
One of both must be erased from static.ini.
* Don't forget to back up the original file in case there's a problem
If you have doubled objects, the list is automatically generated on your desktop.
But if you can't save the mission even though you don't have doubled objects, press shift+tab key together on that screen.
Then it will be shown on the screen what has been objects missing.
If you can't see well due to the interference of the screen, get out of the FMB for a while and go back into the FMB, and you'll see the screen well.
If you have some missing objects, you will have to find them and go on a rough road.
The shift+tab work can be repeated several times until missing objects are eliminated
If you can't find the object no matter how much you look for it, you can use a utility called ''Stand-in_for_missing_objects''
Then I hope you succeed.
My version is 4.12.2m, SAS modact 5.30
Thank you.