switch (substr($table[0], strlen($_POST['dbPrefix']))) {
    case 'Attachments':
    case 'BlogSettings':
    ...
    case 'Trackbacks':
    case 'Users':
}

아래로 수정

switch (strtolower(substr($table[0], strlen($_POST['dbPrefix'])))) {
    case 'attachments':
    case 'blogSettings':
    ...
    case 'trackbacks':
    case 'users':
}