If the database was corrupted beyond recognition (which results in the SQLITE_CORRUPT error), I am afraid there is no way to recover it without a backup copy. This type of corruption suggests there may be a problem with your hardware, OS or disk file system, so you may like to check those and thus prevent other problems not related to Bandwidth Manager.
For a complete backup, including all rules and all settings, simply choose
File - Export Ruleset in the Bandwidth Manager's GUI. It is better to use this method rather than copy the database file, as it will always be in consistent state.
Regarding capturing the protocol, if you have the GUI and the service on the same computer, Wireshark won't capture localhost traffic. You can try
this utility instead.