[Zubersoft]

That means the stamp configuration file is completely missing for some reason, or the packaged fonts aren't being loaded. One thing you can try is going to the user category, add an image file, tap the thumbnail in the list, then tap it again to show the popup and select "Reset all lists". If this doesn't work, it may require resetting the entire application settings under Settings->Other Settings->Reset Settings to Default, or backing up your library under Settings->Backup and Restore->Backup Library, then uninstalling and reinstalling the app.

Mike