Check that your permissions for the pedia Preferences are set correctly. To check that, go into your home folder and navigate to ~/Library/Preferences/com.bruji.gamepedia.plist (or othe pedia program). Select the file and choose 'Get Info' from the File menu. Under the section 'Ownership & Permission' it should say 'Read & Write'.
Alternatively, you can also run 'Repair permissions'. To do that, go into Applications/Utilities and run the program Disk Utility. Select your hard drive and press the 'Repair Disk Permissions' button.