Well, AGetFileVersion that can come in handy in version control and informing the user of the version number of the Application he/she is running doesn't work on 'app' files for one.

It seems to me also that you might need stronger form of security as 'app' files might be giving you a false sense of security since any user with FoxPro installed on his/her machine will be able to run your 'app' file from windows explorer by double clicking on it.