I have Ancestry Family Tree and when I add data in PAF, it does not appear in Ancestry Family Tree. I thought the two programs were supposed to read the same database?
You are correct, both PAF and Ancestry Family Tree read and write the same database files*, but your installations of Ancestry Family Tree and PAF must be looking at the exact same database for the changes to be seen in both programs. You will need to open the same database file in both programs (not at the same time). *Ancestry Family Tree will read and write to a PAF 3.0/4.0 database.