No guarantee this will work, but here's what I would try if I was having this problem.
First I'd try this:I'd export the whole thing as a GEDCOM, and reimport as a new database file (NOT merging or replacing the current database.)Try looking at that data and see if you have the same problem.If not, good.If you do, I'd try the following:
The GEDCOM file is just a text file.After exporting the database to a GEDCOM, you can edit it with MS Notepad.I'd find the name of the guy that's giving me trouble.I'd delete his information and retype it just like it's listed in the file.There might be some kind of odd character in the data that PAF isn't liking.
Beyond that, I don't have a suggestion.If those don't work, I'd be willing to have you send me your GEDCOM, and I'll try to import it and see if I have the same problem. Debbie