Connect the iPad to your computer. BACKUP all of your files by copying all of the files in the unrealBook documents folder to your hard drive. THIS IS IMPORTANT! Make sure you have a backup!
Disconnect the iPad and then press and hold on the unrealBook icon until the icons wiggle and you get the "x" so that you can remove the unrealBook icon. Press the "x" and it will delete the application. THIS WILL ERASE ALL OF YOUR FILES ON THE IPAD !!!!
Re-install unrealBook by purchasing again from the iTunes store (you will not be re-charged since you bought it before).Connect the iPad to your computer and copy your backed up files to the unrealBook documents folder in iTunes.