Kindly follow these steps:
1. Take backup of your company file on SD Card as well as on email.
2. Remove Book Keeper from your phone.
3. Go to Play Store > see if any update for WebView is available, please update it.
4. If there is any update for your phone is pending, please update that too.
5. Install Book Keeper and restore your company (if your company was Local/Dropbox based).
Incase of BKWeb company, don’t need to restore. It will be displayed automatically.
It shall work fine now.