There have been several reports online as well as from WIF 'n Proof users of data loss when upgrading iOS to 5.1. This appears to be a problem with the upgrade process and is most like to occur when upgrading wirelessly.
The recommended procedure is:
1. Make sure you have the latest version of iTunes
2. Plug in your iPhone or iPad to iTunes
3. Preform a full sync with backup
4. Upgrade to iOS 5.1 through iTunes
Since this method may not always preserve your database, export any WIF files you have created or edited before upgrading. If you do lose your data, the next time you start WIF 'n Proof you will see the Registration Screen. Just send me the Registration Request, and I will send you a new Registration Code.
Helen