I have had this problem a few times myself. I think you will find that your file is corrupt and is NOT recoverable. I never managed to recover mine.
In one instance I had a new created backup that I could restore from. Another time I recovered from the auto backup that FTM makes when you close the program. I am not at my home computer at the moment and not sure what the file extention is for the auto backup.
In one instance I had a new created backup that I could restore from. Another time I recovered from the auto backup that FTM makes when you close the program. I am not at my home computer at the moment and not sure what the file extention is for the auto backup.