This is a serious problem.Backup your file (name it backupbadnotes or something)
Do you have your program set to log changes in the file?View/Preferences/File... Log changes.If you have it turned on, it will show changes to your file and you can check for any problems with the last few RINs you entered data for.
1.File/Check Repair. Does the program have a problem with this file?If not, then I would contact support and send them a copy of your file.
If so, get PAF program to repair it.Contact support if it still has a problem.
2.Keep log changes on for awhile.Then you can spot check.You might want to create a special test file at first to check it out.
3.Consider reinstalling PAF 5.
Nevetheless, I would still contact the PAF folks and have them checkout that file.