There has been a lot of discussion online on the developer boards of a bug introduced by the recent upgrade to iOS5.1. Apparently, opening the Apple AppStore App on your iPhone, iPod Touch or iPad may remove all Safari website data. This means that the simple action of opening the AppStore App could destroy your WIF 'n Proof database. In addition, if you elect to backup to iCloud instead of connecting to iTunes on your computer, Apple may erase any data they do not wish to back up. Hopefully, Apple is aware of these issue and will correct the situation. In the meantime, connect to iTunes on your computer to install a new app or to do a backup.
If you regularly backup in iTunes and have lost your database, you can restore from backup. The process is a little lengthy but will recover your data if your last backup included WIF 'n Proof data. If you cannot restore from backup, WIF 'n Proof will require that you request a new registration code. Just send the request on to me.