Sometimes when upgrading from an older version of Jaikoz to a new version with a different database the database doesn’t get updated correctly. If you hit this problem you just need to remove the database (the database is only there for performance/caching reasons it doesnt store anything information not held in the songs themselves or available from the Musicbrainz webservice).
OSX Lion and Later
From Finder, hold down Option Button and select Go menu
Select Library from the list
Preferences : Jaikoz
Delete jaikozdb
Start Jaikoz
OSX Earlier than Lion
Go to Home : Library : Preferences : Jaikoz
Delete jaikozdb
Start Jaikoz
Windows
Go to C:\Users\username\Jaikoz
Delete jaikozdb
Start Jaikoz
Linux
Go to $HOME/.jaikoz/Prefs
Delete jaikozdb
Start Jaikoz