Ok here is my best "get out of jail card". Follow the instructions carefully.
Create a NEW file in FTM 2012 with one person in it. Say yourself if you are in the main corrupted file.
Now from this one person file do a file merge and merge the entire corrupted file into it!!!
So you now have a new file with one duplicate which can easily be fixed but now try the GEDCOM export etc
Let me know what happens?