Reference rewriter: Error

public static string TitleCase(string s)
{
    StringBuilder sb = new StringBuilder();
    if (string.IsNullOrEmpty(s))
    {
        return string.Empty;
    } else{

        sb.Append(s);

    }


    #if true
    sb[0] = char.ToUpper(sb[0]);
    for (int i = 1, imax=sb.Length; i<imax; ++i)
    {
        if (char.IsWhiteSpace(sb[i - 1]))
            sb[i] = char.ToUpper(sb[i]);
        else
            sb[i] = char.ToLower(sb[i]);
    }
    return sb.ToString();
    #else
    return System.Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase(sb);
    #endif
}