It seems the database backup file has corrupted at the time of conversion.

Table of Contents

1. Creating a New Backup File
2. Alternative Solution

Creating a New Backup File

1. Open The Paper Tiger.
2. Navigate to File > Database Backup Manager. (Refer Image 1)
3. It will open Database Backup Manager window (Refer Image 2)
4. Click on Create New Backup File radio button.
5. Click on the Backup Database button.

This will create a new .BAK file, which should solve the problem.

                          Image 1 

                                                                                                   Image 2

Alternative Solution

If this does not work, you can

1. Navigate to your C:\ drive.
2. Navigate to Paper Tiger PT*****41 DBBackups. (Note 1)
3. Move all of the .BAK files out of the folder. (Note 2)
4. Click on the Backup Database button.

Note 1: ***** will be the version of Paper Tiger you are using.

Note 2: We suggest not deleting these files until you have confirmed that this solution has worked for you.