Wow. It would appear that something else is going on besides a file corruption, especially because the "clean" file with one person bombed on making a gedcom.
I would suggest the next steps to be:
1) Uninstall FTM
2) Open your anti-virus software and have it run every diagnostic, disk-cleaning, virus scanning, etc utility that it has.
3) Re-install FTM
Then, try to make a gedcom again.
I would start with the file that has only one person.