Hi Abby, You have already tried the most common solution and it didn't work. Here are two more:
1. Email a copy of your file to yourself as an attachment. See if this version works properly. (Sometimes Windows gets confused about who has permission for what level of access, and this trick usually by-passes this particular problem.)
2. Export your entire file as a gedcom file. Then create a new empty file in PAF and import the gedcom.
Once you have a file that works properly, back it up and then run Check/Repair on it 3 times.
Let us know what worked. If neither one worked, please let us know and we will see what other steps might be needed.